Compound and composition containing same

ABSTRACT

A compound serving as a dichroic pigment which has a maximum absorption wavelength in a range of 350 nm to 510 nm is represented by the following Formula (1): 
     
       
         
         
             
             
         
       
     
     In Formula (1), R 1  represents a hydrogen atom or a C1-C20 alkyl group; R 2  through R 4  are substituents which are not hydrogen atoms and each independently represent a C1-C4 alkyl group; n, m, and p are each independently an integer of 0 to 2; and Ar 1  represents a nitrogen-containing saturated heterocyclic group which is a 5 to 8-membered ring and in which (i) N is bonded to a phenylene group and (ii) at least one β-position is an oxygen atom or a sulfur atom.

TECHNICAL FIELD

The present invention relates to (i) a compound serving as a dichroicpigment and (ii) a composition containing the compound.

BACKGROUND ART

Patent Literature 1 discloses a polarizing film containing a compound(dichroic pigment) which is dispersed in an aligned polymerizable liquidcrystal compound and which absorbs dichroic light. However, PatentLiterature 1 does not disclose a polarizing film which contains adichroic pigment having a maximum absorption wavelength in a range of350 nm to 510 nm and which is thus high in dichroic ratio.

Patent Literature 2 discloses, as a dichroic pigment having a maximumabsorption wavelength in a range of 350 nm to 550 nm, a bisazo pigmenthaving a 1,4-naphthyl structure. However, a polarizing film containingthe bisazo pigment is low in dichroic ratio.

Patent Literature 3 discloses a polarizing film which has a highdichroic ratio. However, a dichroic pigment contained in the polarizingfilm has a maximum absorption wavelength of 518 nm or higher.

CITATION LIST Patent Literature

[Patent Literature 1]

Japanese Patent Application Publication, Tokukai, No. 2007-510946(Publication Date: Apr. 26, 2007)

[Patent Literature 2]

Japanese Examined Patent Application Publication, Tokukosho, No. 63-1357(Publication Date: Jan. 12, 1988)

[Patent Literature 3]

Japanese Patent Application Publication, Tokukai, No. 2013-101328(Publication Date: May 23, 2013)

SUMMARY OF INVENTION Technical Problem

None of Patent Literatures 1 through 3 discloses a polarizing film whichcontains a dichroic pigment having a maximum absorption wavelength in arange of 350 nm to 510 nm and which is thus high in dichroic ratio.Therefore, there are demands for (i) a polarizing film which contains adichroic pigment having a maximum absorption wavelength in a range of350 nm to 510 nm and which is thus high in dichroic ratio, (ii) a novelcompound serving as the dichroic pigment contained in the polarizingfilm, and (iii) a composition containing the compound.

The present invention has been made in view of the problem, and it is amain object of the present invention to provide (i) a novel compoundserving as a dichroic pigment and (ii) a composition containing thecompound.

Solution to Problem

In order to attain the object, the present invention includes thefollowing.

<1> A compound represented by the following Formula (1):

where: R¹ represents a hydrogen atom, a C1-C20 alkyl group, a C1-C20alkoxy group, a C1-C20 acyl group, a C2-C20 alkoxycarbonyl group, aC1-C20 acyloxy group, or —N(R¹⁰)(R¹¹); R¹⁰ represents a C1-C20 acylgroup, a C1-C20 alkylsulfonyl group, or a C6-C20 arylsulfonyl group; andR¹¹ represents a hydrogen atom or a C1-C20 alkyl group; R¹⁰ and R¹¹ canbond to each other, and form, with a nitrogen atom to which R¹⁰ and R¹¹bond, a ring including —N—CO— or —N—SO₂—; at least one hydrogen atom ofany of the alkyl group, the alkoxy group, the acyl group, thealkoxycarbonyl group, the acyloxy group, the alkylsulfonyl group, andthe arylsulfonyl group can be substituted by a halogen atom, a hydroxygroup, an unsubstituted amino group, or a substituted amino group; —O—or —NR²⁰— can be inserted between carbon atoms of any of the alkyl groupand the alkoxy group; and R²⁰ represents a hydrogen atom or a C1-C20alkyl group;

R² through R⁴ are substituents which are not hydrogen atoms and eachindependently represent a C1-C4 alkyl group, a C1-C4 alkoxy group, ahalogen atom, or a cyano group; at least one hydrogen atom of any of thealkyl group and the alkoxy group can be substituted by a halogen atom ora hydroxy group; and n, m, and p are each independently an integer of 0to 2; and

Ar¹ represents a nitrogen-containing saturated heterocyclic group whichis a 5 to 8-membered ring and in which (i) N is bonded to a phenylenegroup and (ii) at least one β-position is an oxygen atom or a sulfuratom, and 1 to 6 of hydrogen atoms bonded to a ring of thenitrogen-containing saturated heterocyclic group can be substituted by aC1-C3 alkyl group.

<2> The compound described in <1>, configured so that the compound isrepresented by the following Formula (1′):

where: R¹ is identical to R¹ described above; and A represents an oxygenatom or a sulfur atom.

<3> The compound described in <1> or <2>, configured so that thecompound has a maximum absorption wavelength in a range of 350 nm to 510nm.<4> A composition including: a polymerizable liquid crystal compound;and a compound described in any one of <1> through <3>.<5> The composition described in <4>, configured so that thepolymerizable liquid crystal compound exhibits a smectic liquid crystalphase.<6> The composition described in <4> or <5>, further containing apolymerization initiator.<7> A polarizing film containing the compound described in any one of<1> through <3>.<8> The polarizing film described in <7>, configured so that a maximumabsorption wavelength (λ_(max1)) of the polarizing film is longer than amaximum absorption wavelength (λ_(max2)) of the compound represented bythe Formula (1) or the Formula (1′).<9> The polarizing film described in <8>, configured so that adifference between the λ_(max1) and the λ_(max2) is 10 nm or more.<10> The polarizing film described in any one of <7> through <9>,configured so that the polarizing film exhibits a Bragg peak in X-raydiffraction measurement.<11> A liquid crystal display device including the polarizing filmdescribed in any one of <7> through <9>.<12> A liquid crystal cell including: a polarizing film described in anyone of <7> through <9>; a liquid crystal layer; and a base.<13> The liquid crystal cell described in <12>, configured so that thepolarizing film is provided between the base and the liquid crystallayer.<14> The liquid crystal cell described in <13>, further including: acolor filter provided between the base and the liquid crystal layer.<15> A circularly polarizing plate including: a polarizing filmdescribed in any one of <7> through <9>; and a quarter-wave plate.<16> An organic EL display device including: a polarizing film describedin any one of <7> through <9>; and an organic EL element.<17> An organic EL display device including: a circularly polarizingplate described in <15>; and an organic EL element.

Advantageous Effects of Invention

A compound in accordance with an embodiment of the present invention isa novel compound serving as a dichroic pigment which has a maximumabsorption wavelength in a range of 350 nm to 510 nm. The compound canadvantageously allow a polarizing film, which has a high dichroic ratio,to be obtained from a composition containing the compound.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view schematically illustrating a producing apparatuswhich continuously produces polarizing films in accordance with anembodiment of the present invention.

FIG. 2 is a front view schematically illustrating a producing apparatuswhich continuously produces circularly polarizing plates havingrespective polarizing films in accordance with an embodiment of thepresent invention.

FIG. 3 is a side view schematically illustrating a configuration of adisplay device including a polarizing film in accordance with anembodiment of the present invention.

FIG. 4 is a side view schematically illustrating another configurationof a display device including a polarizing film in accordance with anembodiment of the present invention.

FIG. 5 is a side view schematically illustrating yet anotherconfiguration of a display device including a polarizing film inaccordance with an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following description will discuss an embodiment of the presentinvention in detail. Note that numerical expressions such as “A to B”herein mean “A or more and B or less”.

<Compound Represented by Formula (1)>

A compound represented by Formula (1) in accordance with an embodimentof the present invention (hereinafter also referred to as “compound(1)”) has two azo groups which are preferably trans azo groups.

R¹ in Formula (1) represents a hydrogen atom, a C1-C20 alkyl group, aC1-C20 alkoxy group, a C1-C20 acyl group, a C2-C20 alkoxycarbonyl group,a C1-C20 acyloxy group, or —N(R¹⁰)(R¹¹), and preferably represents ahydrogen atom, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C1-C20acyl group, a C2-C20 alkoxycarbonyl group, or a C1-C20 acyloxy group.

Examples of the C1-C20 alkyl group encompass unsubstituted linear orbranched alkyl groups such as a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an isobutyl group,a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentylgroup, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonylgroup, and an n-decyl group.

At least one hydrogen atom of the C1-C20 alkyl group can be substitutedby a halogen atom (e.g. fluorine atom), a hydroxy group, or anunsubstituted or substituted amino group. Examples of the substitutedamino group encompass amino groups, each of which is substituted by oneor two C1-C20 alkyl groups, such as an N-methylamino group, anN-ethylamino group, an N,N-dimethylamino group, an N,N-diethylaminogroup. Examples of the alkyl group in which at least one hydrogen atomis substituted by a halogen atom or the like encompass: C1-C20 haloalkylgroups such as a fluoromethyl group, a trifluoromethyl group, apentafluoroethyl group, a nonafluorobutyl group; C1-C20 hydroxyalkylgroups such as a hydroxymethyl group and a 2-hydroxyethyl group; andC1-C20 alkyl groups, each having an unsubstituted or substituted aminogroup, such as an aminomethyl group and a 2-(N,N-dimethylamino)ethylgroup.

Between carbon atoms of the alkyl group, —O— or —NR²⁰— can be inserted.R²⁰ represents a hydrogen atom or a C1-C20 alkyl group. Examples of theC1-C20 alkyl group encompass C1-C20 alkyl groups similar to thosedescribed above. Examples of the alkyl group, in which —O— or —NR²⁰— isinserted between carbon atoms, encompass a methoxymethyl group, a2-ethoxyethyl group, a 2-(2-ethoxyethoxy)ethyl group, and−2-[2-(ethylamino)ethylamino]ethyl group.

Examples of the C1-C20 alkoxy group encompass unsubstituted linear orbranched alkoxy groups such as a methoxy group, an ethoxy group, ann-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxygroup, a tert-butoxy group, an n-pentyloxy group, an isopentyloxy group,a neopentyloxy group, an n-hexyloxy group, an n-heptyloxy group, ann-octyloxy group, an n-nonyloxy group, and an n-decyloxy group.

At least one hydrogen atom of the C1-C20 alkoxy group can be substitutedby a halogen atom (e.g. fluorine atom), a hydroxy group, or anunsubstituted or substituted amino group. Examples of the substitutedamino group encompass amino groups, each of which is substituted by oneor two C1-C20 alkyl groups, such as an N-methylamino group, anN-ethylamino group, an N,N-dimethylamino group, an N,N-diethylaminogroup. Examples of the alkoxy group in which at least one hydrogen atomis substituted by a halogen atom or the like encompass: C1-C20haloalkoxy groups such as a fluoromethoxy group, a trifluoromethoxygroup, a pentafluoroethoxy group, and a nonafluorobutoxy group; C1-C20hydroxyalkoxy groups such as a hydroxymethoxy group and a2-hydroxyethoxy group; and C1-C20 alkoxy groups, each having anunsubstituted or substituted amino group, such as an aminomethoxy groupand a 2-(N,N-dimethylamino)ethoxy group.

Between carbon atoms of the alkoxy group, —O— or —NR²⁰— can be inserted.Examples of alkoxy group, in which —O— or —NR²⁰— is inserted betweencarbon atoms, encompass a methoxymethoxy group, a 2-ethoxyethoxy group,a 2-(2-ethoxyethoxy)ethoxy group, and−2-[2-(ethylamino)ethylamino]ethoxy group.

Examples of the C1-C20 acyl group encompass unsubstituted acyl groupssuch as a formyl group, an acetyl group, an ethylcarbonyl group, ann-propylcarbonyl group, an isopropylcarbonyl group, an n-butylcarbonylgroup, an isobutylcarbonyl group, a tert-butylcarbonyl group, ann-pentylcarbonyl group, an isopentylcarbonyl group, a neopentylcarbonylgroup, an n-hexylcarbonyl group, an n-heptylcarbonyl group, ann-octylcarbonyl group, an n-nonylcarbonyl group, and an n-decylcarbonylgroup.

At least one hydrogen atom of the acyl group can be substituted by ahalogen atom (e.g. fluorine atom), a hydroxy group, or an unsubstitutedor substituted amino group. Examples of the substituted amino groupencompass amino groups, each of which is substituted by one or twoC1-C20 alkyl groups, such as an N-methylamino group, an N-ethylaminogroup, an N,N-dimethylamino group, an N,N-diethylamino group. Examplesof the acyl group in which at least one hydrogen atom is substituted bya halogen atom or the like encompass C1-C20 haloacyl groups such as atrifluoroacetyl group, a pentafluoroethylcarbonyl group, and anonafluorobutylcarbonyl group.

Examples of the C2-C20 alkoxycarbonyl group encompass unsubstitutedalkoxycarbonyl groups such as a methoxycarbonyl group, an ethoxycarbonylgroup, an n-propoxycarbonyl group, an isopropoxycarbonyl group, ann-butoxycarbonyl group, an isobutoxycarbonyl group, atert-butoxycarbonyl group, an n-pentyloxycarbonyl group, anisopentyloxycarbonyl group, a neopentyloxycarbonyl group, ann-hexyloxycarbonyl group, an n-heptyloxycarbonyl group, ann-octyloxycarbonyl group, an n-nonyloxycarbonyl group, and ann-decyloxycarbonyl group.

At least one hydrogen atom of the alkoxycarbonyl group can besubstituted by a halogen atom (e.g. fluorine atom), a hydroxy group, oran unsubstituted or substituted amino group. Examples of the substitutedamino group encompass amino groups, each of which is substituted by oneor two C1-C20 alkyl groups, such as an N-methylamino group, anN-ethylamino group, an N,N-dimethylamino group, an N,N-diethylaminogroup. Examples of the alkoxycarbonyl group in which at least onehydrogen atom is substituted by a halogen atom or the like encompassC2-C20 haloalkoxycarbonyl groups such as a fluoromethoxycarbonyl group,a trifluoromethoxycarbonyl group, a pentafluoroethoxycarbonyl group, anda nonafluorobutoxycarbonyl group.

Examples of the C1-C20 acyloxy group encompass unsubstituted acyloxygroups such as an acetyloxy group, an ethylcarbonyloxy group, ann-propylcarbonyloxy group, an isopropylcarbonyloxy group, ann-butylcarbonyloxy group, an isobutylcarbonyloxy group, atert-butylcarbonyloxy group, an n-pentylcarbonyloxy group, anisopentylcarbonyloxy group, a neopentylcarbonyloxy group, ann-hexylcarbonyloxy group, an n-heptylcarbonyloxy group, ann-octylcarbonyloxy group, an n-nonylcarbonyloxy group, and ann-decylcarbonyloxy group.

At least one hydrogen atom of the acyloxy group can be substituted by ahalogen atom (e.g. fluorine atom), a hydroxy group, or an unsubstitutedor substituted amino group. Examples of the substituted amino groupencompass amino groups, each of which is substituted by one or twoC1-C20 alkyl groups, such as an N-methylamino group, an N-ethylaminogroup, an N,N-dimethylamino group, an N,N-diethylamino group. Examplesof the acyloxy group in which at least one hydrogen atom is substitutedby a halogen atom or the like encompass C1-C20 haloacyloxy groups suchas a fluoroacetyloxy group, a trifluoroacetyloxy group, apentafluoroethylcarbonyloxy group, and a nonafluorobutylcarbonyloxygroup.

R¹⁰ in —N(R¹⁰)(R¹¹) represents a C1-C20 acyl group, a C1-C20alkylsulfonyl group, or a C6-C20 arylsulfonyl group. R¹¹ in —N(R¹⁰)(R¹¹)represents a hydrogen atom or a C1-C20 alkyl group. R¹⁰ and R¹¹ can bondto each other, and form, with a nitrogen atom to which R¹⁰ and R¹¹ bond,a ring including —N—CO— or —N—SO₂—. At least one hydrogen atom of theacyl group, the alkylsulfonyl group, and arylsulfonyl group in R¹⁰ canbe substituted by a halogen atom (e.g. fluorine atom), a hydroxy group,or an unsubstituted or substituted amino group. Examples of thesubstituted amino group encompass amino groups, each of which issubstituted by one or two C1-C20 alkyl groups, such as an N-methylaminogroup, an N-ethylamino group, an N,N-dimethylamino group, anN,N-diethylamino group. Between carbon atoms of the alkyl group in R¹¹,—O— or —NR²⁰— can be inserted. Examples of the C1-C20 acyl group in R¹⁰encompass acyl groups similar to the C1-C20 acyl groups in R¹ describedabove. Examples of the acyl group, in which at least one hydrogen atomof the acyl group is substituted by a halogen atom or the like,encompass groups similar to those in R¹ described above.

Examples of the C1-C20 alkylsulfonyl group encompass unsubstitutedalkylsulfonyl groups such as a methylsulfonyl group, an ethylsulfonylgroup, and an n-propylsulfonyl group. Examples of the group in which atleast one hydrogen atom of the alkylsulfonyl group is substituted by ahalogen atom or the like encompass C1-C20 haloalkylsulfonyl groups suchas a trifluoromethylsulfonyl group, a pentafluoroethylsulfonyl group,and a heptafluoro-n-propylsulfonyl group.

Examples of the C6-C20 arylsulfonyl group encompass a benzenesulfonylgroup, and a p-toluenesulfonyl group. Examples of the group in which atleast one hydrogen atom of the arylsulfonyl group is substituted by ahalogen atom or the like encompass a p-trifluoromethylbenzenesulfonylgroup.

Examples of the C1-C20 alkyl group in R¹¹ encompass alkyl groups similarto the C1-C20 alkyl groups in R¹. Examples of the alkyl group, in whichat least one hydrogen atom of the alkyl group is substituted by ahalogen atom or the like, encompass groups similar to those in R¹described above.

Specific examples of —N(R¹⁰)(R¹¹) encompass an acylamino group, anethylcarbonylamino group, an n-propylcarbonylamino group, anisopropylcarbonylamino group, an n-butylcarbonylamino group, anisobutylcarbonylamino group, a tert-butylcarbonylamino group, ann-pentylcarbonylamino group, an isopentylcarbonylamino group, aneopentylcarbonylamino group, an n-hexylcarbonylamino group, ann-heptylcarbonylamino group, an n-octylcarbonylamino group, ann-nonylcarbonylamino group, an n-decylcarbonylamino group, and atrifluoroacylamino group.

Examples of the ring, which (i) is formed by R¹⁰ and R¹¹ (bonded to eachother) together with a nitrogen atom to which R¹⁰ and R¹¹ bond and (ii)contains —N—CO— or —N—SO₂—, encompass a 2-pyrrolidone-1-yl group.

R¹ is a (i) C1-C10 alkyl group which can have a halogen atom (preferablya fluorine atom), (ii) C1-C20 alkyl group in which —O— is insertedbetween carbon atoms of the alkyl group, (iii) a C1-C10 alkoxy groupwhich can have a halogen atom (preferably a fluorine atom), (iv) aC1-C20 alkoxy group in which —O— is inserted between carbon atoms of thealkoxy group, (v) a C1-C10 acyl group which can have a halogen atom(preferably a fluorine atom), (vi) a C2-C10 alkoxycarbonyl group whichcan have a halogen atom (preferably a fluorine atom), (vii) a C1-C10acyloxy group which can have a halogen atom (preferably a fluorineatom), or (viii) —N(R¹⁰)(R¹¹). R¹⁰ is preferably a C1-C20 acyl groupwhich can have halogen atom (preferably a fluorine atom). R¹¹ ispreferably a hydrogen atom.

R¹ is more preferably (i) a linear C1-C10 alkyl group which can have afluorine atom or (ii) —N(R¹⁰)(R¹¹). R¹⁰ is more preferably a C1-C10 acylgroup which can have a fluorine atom. R¹¹ is preferably a hydrogen atom.

R¹ is particularly preferably a linear C1-C10 alkyl group which can havea fluorine atom.

R² through R⁴ in Formula (1) are substituents which are not hydrogenatoms and each independently represent a C1-C4 alkyl group, a C1-C4alkoxy group, a halogen atom, or a cyano group. R² through R⁴ can eachbe substituted in any position of a phenylene group.

Examples of the C1-C4 alkyl group encompass unsubstituted linear orbranched alkyl groups such as a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an isobutyl group,and a tert-butyl group.

At least one hydrogen atom of the C1-C4 alkyl group can be substitutedby a halogen atom (e.g. fluorine atom) or a hydroxy group. Examples ofthe alkyl group in which at least one hydrogen atom is substituted by ahalogen atom or the like encompass: C1-C4 haloalkyl groups such as afluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group,and a nonafluorobutyl group; and C1-C4 hydroxyalkyl groups such as ahydroxymethyl group and a 2-hydroxyethyl group.

Examples of the C1-C4 alkoxy group encompass unsubstituted linear orbranched alkoxy groups such as a methoxy group, an ethoxy group, ann-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxygroup, and a tert-butoxy group.

At least one hydrogen atom of the C1-C4 alkoxy group can be substitutedby a halogen atom (e.g. fluorine atom) or a hydroxy group. Examples ofthe alkoxy group in which at least one hydrogen atom is substituted by ahalogen atom or the like encompass: C1-C4 haloalkoxy groups such as afluoromethoxy group, a trifluoromethoxy group, a pentafluoroethoxygroup, and a nonafluorobutoxy group; and C1-C4 hydroxyalkoxy groups suchas a hydroxymethoxy group and a 2-hydroxyethoxy group.

n, m, and p in Formula (1) are each independently an integer of 0 to 2,and more preferably 0.

Ar¹ in Formula (1) represents a nitrogen-containing saturatedheterocyclic group which is a 5 to 8-membered ring and in which (i) N isbonded to a phenylene group and (ii) at least one β-position is anoxygen atom or a sulfur atom.

1 to 6 of hydrogen atoms bonded to a ring of the nitrogen-containingsaturated heterocyclic group can be substituted by a C1-C3 alkyl group.Examples of the nitrogen-containing saturated heterocyclic groupencompass groups represented by the following formulas:

Therefore, the compound (1) is particularly preferably a compoundrepresented by Formula (1′) in accordance with an embodiment of thepresent invention (hereinafter, such a compound will also be referred toas “compound (1′)”). R¹ in Formula (1′) is identical to R¹ describedabove; and A represents an oxygen atom or a sulfur atom.

Specific examples of each of the compound (1) and the compound (1′)encompass compounds represented by the following Formulas (1-1) through(1-39):

Among these, the compounds represented by Formula (1-1), Formula (1-2),Formula (1-5), Formula (1-7), Formula (1-8), and Formula (1-16) arepreferable. The compounds represented by Formula (1-2) and Formula (1-5)are more preferable.

The compound (1) can be produced by reacting a compound represented byFormula (2a):

(where R¹ through R³, n, and m are identical to R¹ through R³, n, and mdescribed above.) (hereinafter also referred to as “compound (2a)”) witha compound represented by Formula (2b):

(where R⁴ and p are identical to R⁴ and p described above.)

(hereinafter also referred to as “compound (2b)”) so as to obtain acompound represented by Formula (3a):

(where R¹ through R⁴, n, m, and p are identical to R¹ through R⁴, n, m,and p described above.)

(hereinafter also referred to as “compound (3a)”), and then obtaining,from the compound (3a), a compound represented by Formula (3b):

(where R¹ through R⁴, n, m, and p are identical to R¹ through R⁴, n, m,and p described above.)

(hereinafter also referred to as “compound (3b)”), and then (i) reactingan amino group of the compound (3b) with alkylene halohydrin (e.g.2-iodoethanol) which can have a substituent, so that one hydrogen atomof the amino group of the compound (3b) is substituted by a hydroxyalkylgroup which can have a substituent and then (ii) subjecting thehydroxyalkyl group to a cyclization reaction with formaldehyde, so thata nitrogen-containing saturated heterocyclic group, which is Ar¹, isformed. This process can be carried out according to, for example, themethod disclosed in Chem Bio Chem, 2011, 12, 1712.

The compound (1) can be taken out, after the reaction ends, by anordinary taking-out method such as recrystallization, reprecipitation,extraction, and various methods of chromatography.

The compound (1) is a novel compound which has a maximum absorptionwavelength in a range of 350 nm to 510 nm, preferably in a range of 400nm to 500 nm, more preferably in a range of 410 nm to 490 nm, and stillmore preferably in a range of 420 nm to 480 nm and which serves as adichroic pigment. In particular, a polarizing film, which is obtained byaligning the compound (1) with a polymerizable liquid crystal compound,shows high dichroism. In addition, the compound (1), preferably thecompound (1′), is light-resistant. Therefore a polarizing film includinga compound in accordance with an embodiment of the present invention islight-resistant.

A composition in accordance with an embodiment of the present invention,which composition includes a polymerizable liquid crystal compound andthe compound (1), will be described next. The composition in accordancewith an embodiment of the present invention can include two or morekinds of compounds (1).

<Polymerizable Liquid Crystal Compound>

A polymerizable liquid crystal compound is a compound in which amolecule has a polymerizable group and which exhibits a liquid crystalphase by being aligned, and is preferably a compound which exhibits aliquid crystal phase by being aligned alone.

The “polymerizable group” means a group relevant to a polymerizationreaction, and is preferably a photopolymerizable group. Note that a“polymerizable group” refers to a group which can be involved in apolymerization reaction by, for example, an active radical or an acidgenerated from a polymerization initiator described later. Examples ofthe polymerizable group encompass a vinyl group, a vinyloxy group, a1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, anacryloyloxy group, a methacryloyloxy group, an oxiranyl group, and anoxetanyl group. Among these, an acryloyloxy group, a methacryloyloxygroup, a vinyloxy group, an oxiranyl group, and an oxetanyl group arepreferable, and an acryloyloxy group is more preferable.

The polymerizable liquid crystal compound can be a thermotropic liquidcrystal type or a lyotropic liquid crystal type.

Examples of the polymerizable liquid crystal compound encompass (i) acompound exhibiting a nematic liquid crystal phase, (ii) a compoundexhibiting a smectic liquid crystal phase, and (iii) a compoundexhibiting both a nematic liquid crystal phase and a smectic liquidcrystal phase. The polymerizable liquid crystal compound is preferably acompound exhibiting a smectic liquid crystal phase, and more preferablya compound exhibiting a higher-order smectic liquid crystal phase. Thecomposition in accordance with an embodiment of the present invention,which composition includes a polymerizable liquid crystal compoundexhibiting a smectic liquid crystal phase, can bring about a polarizingfilm having superior polarizability. The composition in accordance withan embodiment of the present invention can include two or more kinds ofpolymerizable liquid crystal compounds.

Even in a case where the compound (1) is being dispersed between densemolecular chains formed by a polymerizable liquid crystal compoundexhibiting a smectic liquid crystal phase, the compound (1) can stillshow high dichroism. Therefore, a composition including the compound (1)can bring about a polarizing film which has a high dichroic ratio.

Examples of the higher-order smectic liquid crystal phase encompass asmectic B phase, a smectic D phase, a smectic E phase, a smectic Fphase, a smectic G phase, a smectic H phase, a smectic I phase, asmectic J phase, a smectic K phase, and a smectic L phase. Among these,a smectic B phase, a smectic F phase, and a smectic I phase arepreferable, and a smectic B phase is more preferable. In a case wherethe smectic liquid crystal phase exhibited by the polymerizable liquidcrystal compound is any of these higher-order smectic phase, it ispossible to obtain a polarizing film having a higher orientationalorder. A polarizing film, which is obtained from a composition includinga polymerizable liquid crystal compound that exhibits a higher-ordersmectic liquid crystal phase in which an orientational order is high,exhibits a Bragg peak in X-ray diffraction measurement, which Bragg peakis derived from a higher-order structure as in a phase such as a hexaticphase and a crystal phase. A “Bragg peak” is a peak derived from surfaceperiodic structure of molecular orientation. A periodic interval (orderperiod) of a polarizing film obtained from the composition in accordancewith an embodiment of the present invention is preferably 0.30 nm to0.50 nm.

The type of liquid crystal phase exhibited by the polymerizable liquidcrystal compound can be checked by, for example, the following method.That is, a proper base material is prepared. Then, the base material iscoated with a solution containing the polymerizable liquid crystalcompound and a solvent, so that a coated film is formed. Then, thecoated film is subjected to a heat treatment or a decompressiontreatment, so that the solvent contained in the coated film is removed.Then, the coated film formed on the base material is heated to anisotropic phase temperature, and is then gradually cooled. This causes aliquid crystal phase to appear. Then, the liquid crystal phase isinspected by (i) texture observation with use of a polarizingmicroscope, (ii) X-ray diffraction measurement, or (iii) differentialscanning calorimetry. In this inspection, for example, cooling thecoated film to a first temperature can confirm that coated film exhibitsa nematic liquid crystal phase. Further cooling the coated filmgradually to a second temperature can confirm that the coated filmexhibits a smectic liquid crystal phase.

The polymerizable liquid crystal composition is preferably a compoundrepresented by Formula (4) (hereinafter also referred to as “compound(4)”):

U¹-V¹-W¹-X¹-Y¹-X²-Y²-X³-W²-V²-U²  (4)

where: X¹, X², and X³ each independently represent (i) a 1,4-phenylenegroup which can have a substituent or (ii) a cyclohexane-1,4-diyl groupwhich can have a substituent, provided that at least one of X¹, X², andX³ is a 1,4-phenylene group which can have a substituent; —CH²— of acyclohexane-1,4-diyl group can be substituted by —O—, —S—, or —NR—; Rrepresents a C1-C6 alkyl group or a phenyl group;

Y¹ and Y² each independently represent a single bond, —CH₂CH₂—, —CH₂O—,—COO—, —OCOO—, —N═N—, —CR^(a)═CR^(b)—, —C≡C—, or —CR^(a)═N—; R^(a) andR^(b) each independently represent a hydrogen atom or a C1-C4 alkylgroup;U¹ represents a hydrogen atom or a polymerizable group;U² represents a polymerizable group;W¹ and W² each independently represent a single bond, —O—, —S—, —COO—,or —OCOO—; andV¹ and V² each independently represent a C1-C20 alkanediyl group whichcan have a substituent, and —CH₂— of the alkanediyl group can besubstituted by —O—, —S—, or —NH—.

In the compound (4), at least one of X¹, X², and X³ is preferably a1,4-phenylene group which can have a substituent.

The 1,4-phenylene group which can have a substituent is preferably anunsubstituted 1,4-phenylene group. The cyclohexane-1,4-diyl group whichcan have a substituent is preferably a trans-cyclohexane-1,4-diyl groupwhich can have a substituent. The trans-cyclohexane-1,4-diyl group whichcan have a substituent is preferably an unsubstitutedtrans-cyclohexane-1,4-diyl group.

Examples of the substituent that can be included in the 1,4-phenylenegroup which can have a substituent or in the cyclohexane-1,4-diyl groupwhich can have a substituent encompass (i) C1-C4 alkyl groups such as amethyl group, an ethyl group, an n-butyl group, (ii) a cyano group, and(iii) a halogen atom.

Y¹ is preferably a single bond, —CH₂CH₂—, or —COO—. Y² is preferably—CH₂CH₂— or —CH₂O—.

U¹ is a hydrogen atom or a polymerizable group, and is preferably apolymerizable group. U² is a polymerizable group. U¹ and U² arepreferably both polymerizable groups, and more preferably bothphotopolymerizable groups. A polymerizable liquid crystal compoundincluding a photopolymerizable group can advantageously be polymerizedunder low temperature conditions.

The polymerizable groups represented by U¹ and U² can be different fromeach other, but are preferably identical. Examples of the polymerizablegroup encompass a vinyl group, a vinyloxy group, a 1-chlorovinyl group,an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, amethacryloyloxy group, an oxiranyl group, and an oxetanyl group. Amongthese, a vinyloxy group, an acryloyloxy group, a methacryloyloxy group,an oxiranyl group, and an oxetanyl group are preferable, and anacryloyloxy group is more preferable.

Examples of the alkanediyl group represented by V¹ and V² encompass amethylene group, an ethylene group, a propane-1,3-diyl group, abutane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diylgroup, a hexane-1,6-diyl group, a heptane-1,7-diyl group, anoctane-1,8-diyl group, a decane-1,10-diyl group, a tetradecane-1,14-diyl group, and an icosane-1,20-diyl group. V¹ and V² are eachpreferably a C2-C12 alkanediyl group, and more preferably a C6-C12alkanediyl group.

Examples of the substituent that can be included in the C1-C20alkanediyl group which can have a substituent encompass a cyano groupand a halogen atom. The alkanediyl group is preferably an unsubstitutedalkanediyl group, and more preferably an unsubstituted linear alkanediylgroup.

It is preferable that W¹ and W² are each independently a single bond or—O—.

Specific examples of the compound (4) encompass a compound representedby the following Formulas (4-1) through (4-43). In a case where thecompound (4) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diylgroup is preferably in a trans-form.

Among these, the compound (4) is preferably at least one selected fromthe group consisting of the compounds represented by Formula (4-5),Formula (4-6), Formula (4-7), Formula (4-8), Formula (4-9), Formula(4-10), Formula (4-11), Formula (4-12), Formula (4-13), Formula (4-14),Formula (4-15), Formula (4-22), Formula (4-24), Formula (4-25), Formula(4-26), Formula (4-27), Formula (4-28), and Formula (4-29).

The composition in accordance with an embodiment of the presentinvention can include two or more kinds of compounds (4). In a casewhere the two or more kinds of polymerizable liquid crystal compoundsare combined, preferably at least one of the two or more kinds ofpolymerizable liquid crystal compounds is the compound (4), and morepreferably two or more of the two or more kinds of polymerizable liquidcrystal compounds are compounds (4). In a case where two or more kindsof polymerizable liquid crystal compounds are combined, it may bepossible to temporarily maintain a liquid crystal phase even at atemperature which is a liquid crystal-crystal phase transitiontemperature or lower. A ratio at which two kinds of polymerizable liquidcrystal compounds are to be combined is ordinarily 1:99 to 50:50,preferably 5:95 to 50:50, and more preferably 10:90 to 50:50.

The compound (4) can be produced by, for example, a method such as thosedisclosed in publicly known literature such as (i) Lub et al. Recl.Trav. Chim. Pays-Bas, 115, 321-328 (1996) and (ii) Japanese Patent No.4719156.

In view of increasing an alignment property of the polymerizable liquidcrystal compound, the polymerizable liquid crystal compound is containedin the composition in accordance with an embodiment of the presentinvention in an amount of preferably 70 parts by mass to 99.5 parts bymass, more preferably 80 parts by mass to 99 parts by mass, still morepreferably 80 parts by mass to 94 parts by mass, and particularlypreferably 80 parts by mass to 90 parts by mass, relative to 100 partsby mass of a solid content of the composition in accordance with anembodiment of the present invention. Note that the solid content refersto a total amount, excluding a solvent, of components in the compositionin accordance with an embodiment of the present invention.

The composition in accordance with an embodiment of the presentinvention preferably contains a polymerization initiator and a solvent,and can further contain a photosensitizer, a polymerization inhibitor,and a leveling agent.

The compound (1) is contained in the composition in accordance with anembodiment of the present invention in an amount of ordinarily not morethan 50 parts by mass, preferably 0.1 parts by mass to 10 parts by mass,and more preferably 0.1 parts by mass to 5 parts by mass, relative to100 parts by mass of the polymerizable liquid crystal compound. In acase where the compound (1) is contained in an amount of not more than50 parts by mass relative to 100 parts by mass of the polymerizableliquid crystal compound, a polarizing film to be obtained tends to havelittle disorder in alignment of the polymerizable liquid crystalcompound and the compound (1).

<Solvent>

A solvent is preferably a solvent in which a polymerizable liquidcrystal compound and the compound (1) can be completely dissolved. Thesolvent is also preferably a solvent that is inactive in apolymerization reaction of a polymerizable liquid crystal compound.

Examples of the solvent encompass alcohol solvents such as methanol,ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethyleneglycol methyl ether, ethylene glycol butyl ether, propylene glycolmonomethyl ether; ester solvents such as ethyl acetate, butyl acetate,ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycolmethyl ether acetate, and ethyl lactate; ketone solvents such asacetone, methyl ethyl ketone, cyclopentanone, cyclohexanone,2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solventssuch as pentane, hexane, and heptane; aromatic hydrocarbon solvents suchas toluene and xylene; nitrile solvents such as acetonitrile; ethersolvents such as tetrahydrofuran and dimethoxyethane; andchlorine-containing solvents such as chloroform and chlorobenzene. Asingle one of these solvents can be used alone, or two or more of thesesolvents can be used in combination.

In a case where the composition in accordance with an embodiment of thepresent invention contains a solvent, the solvent is preferablycontained in an amount of 50% by mass to 98% by mass relative to thetotal amount of the composition in accordance with an embodiment of thepresent invention. In other words, a solid content of the composition inaccordance with an embodiment of the present invention is preferably 2%by mass to 50% by mass. In a case where the solid content is not morethan 50% by mass, the composition in accordance with an embodiment ofthe present invention becomes less viscous. This tends to cause apolarizing film, which is obtained from the composition in accordancewith an embodiment of the present invention, to be substantially uniformin thickness and less likely to be uneven. The solid content can beappropriately decided in view of a thickness of a polarizing film to beproduced.

<Polymerization Initiator>

A polymerization initiator is a compound which can initiate apolymerization reaction of a polymerizable liquid crystal compound. Thepolymerization initiator is preferably a photopolymerization initiatorthat generates an active radical by an effect of light.

Examples of the polymerization initiator encompass a benzoin compound, abenzophenone compound, an alkylphenone compound, an acylphosphine oxidecompound, a triazine compound, an iodonium salt, and a sulfonium salt.

Examples of the benzoin compound encompass benzoin, benzoin methylether, benzoin ethyl ether, benzoin isopropyl ether, and benzoinisobutyl ether.

Examples of the benzophenone compound encompass benzophenone, methylo-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenylsulfide, 3,3′,4,4′-tetra(tert-butylperoxycarbonyl)benzophenone, and2,4,6-trimethylbenzophenone.

Examples of the alkylphenone compound encompass oligomers ofdiethoxyacetophenone,2-methyl-2-morpholino-1-(4-methylthiophenyl)propane-1-one,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one,2-hydroxy-2-methyl-1-phenylpropane-1-one,1,2-diphenyl-2,2-dimethoxyethane-1-one,2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propane-1-one,1-hydroxycyclohexylphenylketone, and2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane-1-one.

Examples of the acylphosphine oxide compound encompass a2,4,6-trimethylbenzoyl diphenylphosphine oxide and abis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

Examples of the triazine compound encompass2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine,2,4-bis(trichloromethyl)-6-(4-methoxy naphthyl)-1,3,5-triazine,2,4-bis(trichloromethyl)-6-(4-methoxy styryl)-1,3,5-triazine,2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)ethenyl]-1,3,5-triazine,2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine,2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine,and−2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine.

Examples of each of the iodonium salt and the sulfonium salt encompasssalts represented by the following formula:

A single one of these polymerization initiators can be used alone, ortwo or more of these polymerization initiators can be used incombination.

The polymerization initiator can be a commercial product. Examples ofthe commercially available polymerization initiator encompass Irgacure(registered trademark) 907, 184, 651, 819, 250, and −369 (manufacturedby Ciba Specialty Chemicals Inc.); SEIKUOL (registered trademark) BZ, Z,and BEE (manufactured by Seiko Chemical Co., Ltd.); Kayacure (registeredtrademark) BP100 and UVI-6992 (manufactured by The Dow ChemicalCompany); ADEKA OPTOMER SP-152 and SP-170 (manufactured by ADEKACORPORATION); TAZ-A and TAZ-PP (manufactured by NIHON SIBER HEGNERK.K.); and TAZ-104 (manufactured by SANWA CHEMICAL CO., LTD.)

In a case where the composition in accordance with an embodiment of thepresent invention contains a polymerization initiator, thepolymerization initiator is to be contained in the composition inaccordance with an embodiment of the present invention in an amount ofordinarily 0.1 parts by mass to 30 parts by mass, preferably 0.5 partsby mass to 10 parts by mass, and more preferably 0.5 parts by mass to 8parts by mass relative to 100 parts by mass of a polymerizable liquidcrystal compound, so that alignment of the polymerizable liquid crystalcompound is less likely to be disturbed.

<Photosensitizer>

In a case where the composition in accordance with an embodiment of thepresent invention contains a photopolymerization initiator, thecomposition in accordance with an embodiment of the present inventionpreferably contains a photosensitizer. In a case where the compositionin accordance with an embodiment of the present invention contains aphotopolymerization initiator and a photosensitizer, a polymerizationreaction of a polymerizable liquid crystal compound tends to bepromoted. Examples of the photosensitizer encompass xanthone compoundssuch as xanthone and thioxanthone (e.g. 2,4-diethyl thioxanthone and−2-isopropyl thioxanthone); anthracene compounds such as anthracene andalkoxy group-containing anthracene (e.g. dibutoxyanthracene); andphenothiazine; and rubrene.

In a case where the composition in accordance with an embodiment of thepresent invention contains a photosensitizer, the photosensitizer is tobe contained in the composition in accordance with an embodiment of thepresent invention in an amount of preferably 0.1 parts by mass to 30parts by mass, more preferably 0.5 parts by mass to 10 parts by mass,and still more preferably 0.5 parts by mass to 8 parts by mass, relativeto 100 parts by mass of a polymerizable liquid crystal compound.

<Polymerization Inhibitor>

Examples of the polymerization inhibitor encompass radical scavengerssuch as hydrochinone, alkoxy group-containing hydrochinone, alkoxygroup-containing catechol (e.g. butylcatechol), pyrogallol,2,2,6,6-tetramethyl-1-piperidinyloxy radical; thiophenols;β-naphthylamines; and β-naphthols.

In a case where the composition in accordance with an embodiment of thepresent invention contains a polymerization inhibitor, it is possible tocontrol a degree of progress of a polymerization reaction of apolymerizable liquid crystal compound.

In a case where the composition in accordance with an embodiment of thepresent invention contains a polymerization inhibitor, thepolymerization inhibitor is to be contained in the composition inaccordance with an embodiment of the present invention in an amount ofpreferably 0.1 parts by mass to 30 parts by mass, more preferably 0.5parts by mass to 10 parts by mass, and still more preferably 0.5 partsby mass to 8 parts by mass, relative to 100 parts by mass of apolymerizable liquid crystal compound.

<Leveling Agent>

The leveling agent, which is an additive that has a function ofadjusting fluidity of the composition in accordance with an embodimentof the present invention so as to further level a coated film to beobtained by application of the composition in accordance with anembodiment of the present invention. Examples of the leveling agentencompass a surfactant. Examples of a preferable leveling agentencompass (i) a leveling agent containing a polyacrylate compound as amain component and (ii) a leveling agent containing a fluorineatom-containing compound as a main component.

Examples of the leveling agent containing a polyacrylate compound as amain component encompass BYK-350, BYK-352, BYK-353, BYK-354, BYK-355,BYK-358N, BYK-361N, BYK-380, BYK-381, and BYK-392 (manufactured byBYK-Chemie GmbH).

Examples of the leveling agent containing a fluorine atom-containingcompound as a main component encompass (i) MEGAFACE (registeredtrademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-471,F-477, F-479, F-482, F-483 (manufactured by DIC Corporation); Surflon(registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105,KH-40, and SA-100 (manufactured by AGC SEIMI CHEMICAL CO., LTD.); E1830and E5844 (manufactured by DAIKIN Fine Chemicals Research Center); FTOPEF301, EF303, EF351, and EF352 (manufactured by Mitsubishi MaterialsElectronic Chemicals Co., Ltd.).

In a case where the composition in accordance with an embodiment of thepresent invention contains a leveling agent, the leveling agent is to becontained in the composition in accordance with an embodiment of thepresent invention in an amount of preferably 0.3 parts by mass to 5parts by mass, and more preferably 0.5 parts by mass to 3 parts by mass,relative to 100 parts by mass of a polymerizable liquid crystalcompound.

In a case where the amount of leveling agent contained falls within theabove ranges, (i) it is easy to horizontally align a polymerizableliquid crystal compound and (ii) a polarizing film to be obtained tendsto be smooth. If the amount of leveling agent contained relative to theweight of polymerizable liquid crystal compound falls outside the rangesabove, then a polarizing film to be obtained is likely to be easilyuneven. The composition in accordance with an embodiment of the presentinvention can contain two or more kinds of leveling agents.

<Method for Producing Polarizing Film>

A polarizing film in accordance with the present invention, which filmcontains the compound (1), can be obtained by, for example, applying,onto a substrate, the composition in accordance with an embodiment ofthe present invention. The polarizing film is preferably produced by amethod including the steps (A) through (C) below:

(A) applying the composition in accordance with an embodiment of thepresent invention onto a base material or onto a surface of a basematerial on which surface an alignment film is formed;(B) aligning (i) a polymerizable liquid crystal compound contained in acoated film thus formed and (ii) the compound (1) contained in thecoated film; and(C) polymerizing the polymerizable liquid crystal compound, having beenaligned, by irradiating the polymerizable liquid crystal compound withan active energy ray.

<Step (A)>

<Base Material>

The base material may be a glass base material or a resin base materialbut is preferably a resin base material. Using a film base material madefrom resin makes it possible to produce a polarizing film which is thin.

The resin base material is preferably a transparent resin base material.“Transparent resin base material” refers to light-transmissive basematerial capable of transmitting light, particularly visible light.“Light-transmissive” refers to a property in which luminosity correctiontransmittance is 80% or more with respect to light waves having awavelength in a range from 380 nm to 780 nm.

The base material is preferably a phase-difference film having aquarter-wave plate function (such a film is hereinafter also referred toas a “quarter-wave plate”). Using a quarter-wave plate as the basematerial makes it possible to obtain a circularly polarizing plate.

In a case where a quarter-wave plate is used, it is preferable todispose the polarizing film and the quarter-wave plate in a manner suchthat a transmission axis of the polarizing film and a slow axis (lightaxis) of the quarter-wave plate form an angle that is substantially 45°.“Substantially 45°” refers, ordinarily, to a range of 45°±5°. It is alsopossible to obtain a circularly polarizing plate which functions as anoptical compensation film (polarizing film) by causing the respectivelight axes of the polarizing film and the quarter-wave plate to bealigned or to intersect orthogonally.

The quarter-wave plate ordinarily has an optical characteristicrepresented by Formula (40) and preferably has an optical characteristicrepresented by Formula (41).

100 nm<Re(550)<160 nm  (40)

130 nm<Re(550)<150 nm  (41)

Where Re (550) represents in-plane phase difference value at awavelength of 550 nm.

Furthermore, the quarter-wave plate preferably has a reverse wavelengthdispersion property. “Reverse wavelength dispersion property” refers toa property where an in-plane phase difference at a short wavelength isgreater than an in-plane phase difference at a long wavelength. Thereverse wavelength dispersion property preferably satisfies the opticalcharacteristics represented by Formula (50) and Formula (51).

Re(450)/Re(550)<1.00  (50)

1.00≦Re(630)/Re(550)  (51)

Where Re (λ) represents an in-plane phase difference with respect tolight having a wavelength of λ nm. With a circularly polarizing platewhich includes a quarter-wave plate having the optical characteristicsrepresented by Formula (50) and Formula (51), it is possible to obtain acharacteristic of uniform polarization conversion with respect to lightof each wavelength in the visible light range. Such a circularlypolarizing plate therefore tends to excel in terms ofantireflectiveness.

The base material may be a phase-difference film having a half-waveplate function.

Examples of resin of which the plastic base material can be made includepolyolefins such as polyethylene, polypropylene, and a norbornenepolymer; cyclic olefinic resins; polyvinyl alcohol; polyethyleneterephthalate; polymethacrylic acid ester; polyacrylic ester; celluloseesters such as triacetyl cellulose, diacetyl cellulose, and celluloseacetate propionate; polyethylene naphthalate; polycarbonate;polysulfone; polyether sulfone; polyether ketone; polyphenylene sulfideand polyphenylene oxide; and the like. The resin is preferably celluloseester, cyclic olefinic resin, polycarbonate, polyether sulfone,polyethylene terephthalate, or polymethacrylic acid ester.

Cellulose ester is a compound obtained by esterifying at least a part ofa hydroxyl group contained in cellulose. Cellulose ester is available asa commercial product. A base material containing cellulose ester is alsoavailable as a commercial product. Examples of a commercially availablebase material containing cellulose ester include: “Fuji TAC (registeredtrademark) film” (manufactured by FujiFilm Corporation); “KC8UX2M”,“KC8UY”, and “KC4UY” (each manufactured by KONICA MINOLTA JAPAN, INC.).

Cyclic olefinic resin is a resin including a polymer or copolymer of acyclic olefin such as a norbornene monomer or polycyclic norbornenemonomer. The cyclic olefinic resin may include a ring-opened structureand may be a resin obtained by hydrogenating a cyclic olefinic resincontaining a ring-opened structure. The cyclic olefinic resin maycontain a structural unit derived from chain olefin and may contain astructural unit derived from a vinyl aromatic compound, to the extentthat transparency of the cyclic olefinic resin is not greatly impairedand hygroscopicity of the cyclic olefinic resin is not greatlyincreased. The cyclic olefinic resin may have a polar group introducedin a molecule thereof.

Examples of the chain olefin include ethylene and propylene. Examples ofthe vinyl aromatic compound include styrene, α-methylstyrene, and astyrene which can have an alkyl group.

In a case where the cyclic olefinic resin is a copolymer of (i) cyclicolefin and (ii) a chain olefin or a vinyl aromatic compound, astructural unit derived from the cyclic olefin is contained in an amountthat is ordinarily 50 mol % or less and preferably 15 mol % to 50 mol %,relative to all structural units of the copolymer.

In a case where the cyclic olefinic resin is a terpolymer composed ofcyclic olefin, a chain olefin, and a vinyl aromatic compound, astructural unit derived from the chain olefin is contained in an amountthat is ordinarily 5 mol % to 80 mol % relative to all structural unitsof the copolymer, and a structural unit derived from the vinyl aromaticcompound is contained at a proportion that is ordinarily 5 mol % to 80mol % relative to all structural units of the copolymer. Such aterpolymer is advantageous in that it enables a relative reduction inthe used amount cyclic olefin which is costly.

The cyclic olefinic resin is available as a commercial product. Examplesof commercially available cyclic olefinic resins include “Topas”(Registered Trademark) (manufactured by Ticona (Germany)), “ARTON”(Registered Trademark) (manufactured by JSR Corporation), “ZEONOR”(Registered Trademark) and “ZEONEX” (Registered Trademark) (eachmanufactured by Zeon Corporation), and “APEL” (Registered Trademark)(manufactured by Mitsui Chemicals, Inc.). Such a cyclic olefinic resincan be made into the base material by film formation by, for example,publicly-known means such as a solvent cast method or a melt extrusionmethod. Examples of commercially available base materials containingcyclic olefinic resin include “Esushina” (Registered Trademark) and“SCA40” (Registered Trademark) (each manufactured by SEKISUI CHEMICALCO., LTD.), and “ZEONOR FILM” (Registered Trademark) (manufactured byOptes Co., Ltd.).

The base material may be subjected to a surface treatment. Examples of amethod for the surface treatment include a method of corona treating orplasma treating a surface of the base material, under atmosphereconditions ranging from a vacuum to atmospheric pressure; a method oflaser treating a surface of the base material; a method of ozonetreating a surface of the base material; a method of performing asaponification treatment on a surface of the base material; a method offlame treating a surface of the base material; a method of applying acoupling agent to a surface of the base material; a method of performinga primer treatment on a surface of the base material; and a graftpolymerization method involving (i) causing a reactive monomer orreactive polymer to adhere to a surface of the base material and (ii)thereafter, causing a reaction by irradiating the base material withradiation, plasma, or ultraviolet rays. Of the above, it is preferableto use the method of corona treating or plasma treating a surface of thebase material, under atmosphere conditions ranging from a vacuum toatmospheric pressure.

Examples of a method of corona treating or plasma treating a surface ofthe base material include: a method of surface treating the basematerial by placing the base material between opposing electrodes andcausing discharge of corona or plasma, under a pressure at or nearatmospheric pressure; a method of (i) causing gas to flow betweenopposing electrodes, (ii) making the gas into plasma between theelectrodes, and (iii) blowing the plasma gas onto the base material; anda method of surface treating the base material with glow dischargeplasma generated under low pressure.

Of the above, it is preferable to use the method of surface treating thebase material by placing the base material between opposing electrodesand causing discharge of corona or plasma, under a pressure at or nearatmospheric pressure or the method of (i) causing gas to flow betweenopposing electrodes, (ii) making the gas into plasma between theelectrodes, and (iii) blowing the plasma gas onto the base material. Thecorona treatment or plasma surface treatment is ordinarily carried outby using a commercially available surface treatment device.

The base material may have a protective film on a surface facing awayfrom the surface on which the composition in accordance with anembodiment of the present invention is applied. Examples of theprotective film include films made from such materials as polyethylene,polyethylene terephthalate, polycarbonate, and polyolefin, and a filmmade from such materials which further has an adhesive layer. Of suchfilms, a film made from polyethylene terephthalate is preferable becauseit exhibits little thermal deformation during drying. Providing aprotective film on a surface facing away from the surface on which thepresent composition is applied makes it possible to prevent film shakingand slight vibration of the coated surface during conveyance of the basematerial, thus improving uniformity of the coating film.

The base material preferably has a small thickness. This is because abase material which is thin has a small mass and thus can be handledpractically. Note, however, that a base material whose thickness isexcessively small tends to have less strength and inferiorprocessability. The base material has a thickness ordinarily of 5 μm to300 μm and preferably of 20 μm to 200 μm.

The base material has a length, as measured in the longitudinaldirection, which is ordinarily 10 m to 3000 m and preferably 100 m to2000 m. The base material has a width, as measured in the widthwisedirection, which is ordinarily 0.1 m to 5 m and preferably 0.2 m to 2 m.

<Alignment Film>

The alignment film for the present invention is a film that has analignment regulating force by which the polymerizable liquid crystalcompound is subjected to alignment in a desired direction.

The alignment film preferably has (i) solvent resistance such that thealignment film is not dissolved by, for example, application of thecomposition in accordance with an embodiment of the present inventionand (ii) heat resistance so as to withstand a heat treatment carried outto remove the solvent and align the polymerizable liquid crystalcompound. Examples of the alignment film include an alignment filmcontaining an alignment polymer, a photoalignment film, and a groovealignment film which achieves alignment by a pattern of depressions andprotrusions or a plurality of grooves formed in its surface.

Examples of the alignment polymer include: polyamides or gelatins eachof which has an amide bond in a molecule thereof; a polyimide which hasan imide bond in a molecule thereof, polyamic acid which is ahydrolysate of the polyimide, polyvinyl alcohol, alkyl-modifiedpolyvinyl alcohol, polyacrylamide, polyoxazole, polyethylenimine,polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylicesters. Of the above, polyvinyl alcohol is preferable. Two or morealignment polymers may be used in combination.

An alignment film containing an alignment polymer is normally formed ona surface of a base material by applying, to the base material, acomposition in which an alignment polymer is dissolved in a solvent(hereinafter also referred to as an alignment polymer composition), andremoving the solvent, or by applying the alignment polymer compositionto the base material, removing the solvent, and carrying out rubbing (arubbing method).

Examples of the solvent include water; alcohol solvents such asmethanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol,methyl cellosolve, butyl cellosolve, and propylene glycol monomethylether; ester solvents such as ethyl acetate, butyl acetate, ethyleneglycol methyl ether acetate, γ-butyrolactone, propylene glycol methylether acetate, and ethyl lactate; ketone solvents such as acetone,methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone,and methyl isobutyl ketone; aliphatic hydrocarbon solvents such aspentane, hexane, and heptane; aromatic hydrocarbon solvents such astoluene and xylene; nitrile solvents such as acetonitrile; ethersolvents such as tetrahydrofuran and dimethoxyethane; chlorinatedhydrocarbon solvents such as chloroform and chlorobenzene; and the like.A single one of these solvents can be used alone, or two or more ofthese solvents can be used in combination.

The alignment polymer contained in the alignment polymer compositiononly needs to have a concentration falling within a range that allowsmaterial(s) of the alignment polymer to be completely dissolved in thesolvent. The concentration is preferably 0.1 mass % to 20 mass %, andmore preferably approximately 0.1 mass % to 10 mass % in solid contentterms, relative to the solution.

A commercially available alignment film material may be used as-is asthe alignment polymer composition. Examples of commercially availablealignment film materials include SUNEVER (Registered Trademark)(manufactured by NISSAN CHEMICAL INDUSTRIES, LTD.) and OPTMER(Registered Trademark) (manufactured by JSR Corporation).

Known methods can be used for applying the alignment polymer compositionto a base material. Such known methods include: application methods suchas spin coating, extrusion, gravure coating, die coating, slit coating,bar coating, and an applicator method; and printing methods such asflexography. In a case where a polarizing film in accordance with anembodiment of the present invention is to be produced via a continuousroll-to-roll production method (described later), the method employedfor applying the alignment polymer composition is ordinarily gravurecoating, die coating, or a printing method such as flexography.

Examples of methods for removing the solvent contained in the alignmentpolymer composition include natural drying, draught drying, heat drying,and drying under reduced pressure.

The alignment film is subjected to rubbing (a rubbing method), asnecessary, in order to give alignment regulating force to the alignmentfilm. By selecting a direction of the rubbing, it is possible todiscretionarily control a direction of the alignment regulating force.

Examples of methods for giving alignment regulating force via a rubbingmethod include a method in which an alignment polymer film, which hasbeen formed on a surface of a base material by applying an alignmentpolymer composition to the base material and annealing the alignmentpolymer composition, is brought into contact with a rubbing roller whichis wound with a rubbing cloth and is rotating.

A photoalignment film is normally formed on a surface of a base materialby applying, to the base material, a composition containing (i) aphotoreactive group-containing polymer or a photoreactivegroup-containing monomer and (ii) a solvent (such a composition ishereinafter sometimes referred to as a “composition for photoalignmentfilm formation”), and irradiating, with light (preferably polarized UVlight), the base material to which the composition has been applied. Thephotoalignment film is more preferable in that a direction of thealignment regulating force can be discretionarily controlled byselecting a polarization direction of light with which to irradiate thebase material to which the composition has been applied.

A photoreactive group refers to a group that generates liquid crystalalignment power upon being irradiated with light. Specific examples of aphotoreactive group include a group that contributes to a photoreactionin which liquid crystal alignment power originates, such as molecularalignment induction or a molecular isomerization reaction caused bylight irradiation, a dimerization reaction caused by light irradiation,a photocrosslinking reaction caused by light irradiation, or aphotolysis reaction caused by light irradiation. In particular, a groupthat contributes to a dimerization reaction or a photocrosslinkingreaction is preferable in terms of excellence in alignment property. Agroup that has an unsaturated bond, particularly a double bond ispreferable as a photoreactive group. A group that has at least one bondselected from the group consisting of a carbon-carbon double bond (C═Cbond), a carbon-nitrogen double bond (C═N bond), a nitrogen-nitrogendouble bond (N═N bond), and a carbon-oxygen double bond (C═O bond) isparticularly preferable as a photoreactive group.

Examples of the photoreactive group having a C═C bond include a vinylgroup, a polyene group, a stilbene group, a stilbazole group, astilbazolium group, a chalcone group, a cinnamoyl group, and the like.Examples of the photoreactive group having a C═N bond include groupshaving structures such as aromatic Schiff base and aromatic hydrazone.Examples of the photoreactive group having an N═N bond include anazobenzene group, an azonaphtalene group, a heteroaromatic ring azogroup, a bisazo group, a formazan group, and a group having anazoxybenzene structure. Examples of the photoreactive group having a C═Obond include a benzophenone group, a coumarin group, an anthraquinonegroup, and a maleimide group. These groups can have any of substituentssuch as an alkyl group, an alkoxy group, an aryl group, an allyloxygroup, a cyano group, an alkoxycarbonyl group, a hydroxyl group, asulfonic group, an alkyl halide group, and the like.

Among those, it is preferable to employ a photoreactive group which isinvolved in a photodimerization. The cinnamoyl group and the chalconegroup are preferable because an amount of polarized radiation necessaryfor photoalignment is relatively small and a photoalignment film whichis excellent in thermal stability and in temporal stability is morelikely to be obtained. A polymer having a photoreactive group isparticularly preferably a polymer having a cinnamoyl group in which aterminal of a polymer-side chain has a cinnamic acid structure.

Examples of a solvent to be contained in the composition forphotoalignment film formation include solvents similar to those to beincluded in the alignment polymer composition. The solvent can beselected as necessary in accordance with a solubility of thephotoreactive group-containing polymer or photoreactive group-containingmonomer.

The photoreactive group-containing polymer or photoreactivegroup-containing monomer is contained in the composition forphotoalignment film formation in an amount which can be adjusted asnecessary in accordance with, for example, (i) the type of polymer ormonomer and (ii) a desired thickness of the photoalignment film. Theamount is, however, preferably at least 0.2% by mass and more preferably0.3% by mass to 10% by mass. The composition for photoalignment filmformation can contain polymeric materials such as polyvinyl alcohol andpolyimide, and/or a photosensitizer, provided that a characteristic ofthe photoalignment film is not greatly impaired.

A method for applying the composition for photoalignment film formationto a base material can be a method similar to the method for applyingthe alignment polymer composition to a base material. A method forremoving the solvent from the composition for photoalignment filmformation can be, for example, a method identical to the method forremoving the solvent from the alignment polymer composition.

Polarized light irradiation can be carried out in a mode in whichpolarized UV light is irradiated directly onto a composition obtained byremoving the solvent from the composition for photoalignment filmformation, the composition having been applied to the base material, orin a mode in which the composition is irradiated with polarized lightthat is incident on the base material and then is transmitted throughthe base material. The polarized light is particularly preferablysubstantially parallel light. Polarized light with which to irradiatethe composition need only have a wavelength in a wavelength region inwhich a photoreactive group of the photoreactive group-containingpolymer or the photoreactive group-containing monomer can absorb lightenergy. Specifically, the polarized light with which to irradiate thecomposition is particularly preferably UV (ultraviolet ray) having awavelength in a range of 250 nm to 400 nm. Examples of a light sourcethat is used in the polarized radiation include a xenon lamp, a highpressure mercury lamp, an extra-high pressure mercury lamp, a metalhalide lamp, and an ultraviolet light lasers such as KrF or ArF lasers.Out of these examples, a high pressure mercury lamp, an extra-highpressure mercury lamp, or a metal halide lamp is more preferably used.These lamps are preferable because they achieve a high light emissionintensity in emitting an ultraviolet ray at a wavelength of 313 nm. Bycausing the light source to emit light so that the light passes throughan appropriate polarizer, it is possible to emit polarized UV light.Examples of the polarizer include: a polarizing filter; polarizingprisms such as a Glan-Thompson prism and a Glan-Taylor prism; and a wiregrid type polarizer.

Note that, in a case where masking is carried out during rubbing orpolarized light irradiation, it is possible to form a plurality ofregions (patterns) that differ in direction of liquid crystal alignment.

A groove alignment film is a film which achieves liquid crystalalignment by a pattern of depressions and protrusions or a plurality ofgrooves formed in its surface H. V. Kennel et al. have reported the factthat in a case where liquid crystal molecules are placed on a basematerial having a plurality of evenly-spaced linear grooves, the liquidcrystal molecules become aligned along the direction of the grooves((Physical Review A24 (5) p. 2713, 1981).

Specific examples of methods for forming a groove alignment film on asurface of a base material include: a method of forming a pattern ofdepressions and protrusions by (i) exposing a surface of aphotosensitive polyimide to light through an exposure mask having arepeating pattern of slits and (ii) thereafter, removing unnecessarypolyimide film by carrying out development and a rinse treatment; amethod involving (i) forming a UV curable resin layer on a plate-likematrix whose surface is provided with grooves, (ii) transferring theresin layer to a base material film, and then (iii) curing the resinlayer; and a method involving (i) conveying a base material film onwhich a UV curable resin layer has been formed, (ii) pressing aroll-like matrix having a plurality of grooves onto a surface of the UVcurable resin layer so as to form depressions and protrusions, and (iii)subsequently curing the resin layer. For example, the methods disclosedin Japanese Patent Application Publication, Tokukaihei, No. 6-34976 andJapanese Patent Application Publication, Tokukai, No. 2011-242743 may beused.

Of the above methods, it is preferable to use the method involvingpressing the roll-like matrix having a plurality of grooves onto thesurface of the UV curable resin layer so as to form depressions andprotrusions and subsequently curing the resin layer. In terms ofdurability, stainless steel (SUS) can be used for the roll-like matrix.

For the UV curable resin, it is possible to use a polymer of amonofunctional acrylate, a polymer of a multifunctional acrylate, or apolymer of a mixture of both a monofunctional acrylate and amultifunctional acrylate.

A monofunctional acrylate is a compound which has, in a moleculethereof, one group selected from the group consisting of an acryloyloxygroup (CH₂═CH—COO—) and a methacryloyloxy group (CH₂═C (CH₃)—COO—). Sucha group selected from the group consisting of an acryloyloxy group and amethacryloyloxy group is hereinafter also referred to as(meth)acryloyloxy group.

Examples of the monofunctional acrylate having one (meth)acryloyloxygroup include an alkyl(meth)acrylate having 4 to −16 carbon atoms, aβ-carboxyalkyl (meth)acrylate having 2 to 14 carbon atoms, an alkylatedphenyl (meth)acrylate having 2 to 14 carbon atoms,methoxypolyethyleneglycol (meth)acrylate, phenoxy polyethylene glycol(meth)acrylate, and isobornyl (meth)acrylate.

A multifunctional acrylate is, ordinarily, a compound having two to six(meth)acryloyloxy groups in a molecule thereof.

Examples of a bifunctional acrylate having two (meth)acryloyloxy groupsinclude 1,3-butanediol di(meth)acrylate, 1,3-butanediol (meth)acrylate,1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate,diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate,triethylene glycol di(meth)acrylate, tetraethylene glycoldi(meth)acrylate, polyethylene glycol diacrylate, bis(acryloyloxyethyl)ether of bisphenol A, ethoxylated bisphenol A di(meth)acrylate,propoxylated neopentyl glycol di(meth)acrylate, ethoxylated neopentylglycol di(meth)acrylate, and 3-methyl pentanediol di(meth)acrylate.

Examples of a multifunctional acrylate having three to six(meth)acryloyloxy groups include:

trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate,tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate, ethoxylatedtrimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropanetri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol penta(meth)acrylate, dipentaerythritolhexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate,tripentaerythritol penta(meth)acrylate, tripentaerythritolhexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate,tripentaerythritol octa(meth)acrylate;a product of reacting pentaerythritol tri(meth)acrylate and an acidanhydride, a product of reacting dipentaerythritol penta(meth)acrylateand an acid anhydride, a product of reacting tripentaerythritolhepta(meth)acrylate and an acid anhydride;caprolactone-modified trimethylolpropane tri(meth)acrylate,caprolactone-modified pentaerythritol tri(meth)acrylate,caprolactone-modified tris(2-hydroxyethyl) isocyanuratetri(meth)acrylate, caprolactone-modified pentaerythritoltetra(meth)acrylate, caprolactone-modified dipentaerythritolpenta(meth)acrylate, caprolactone-modified dipentaerythritolhexa(meth)acrylate, caprolactone-modified tripentaerythritoltetra(meth)acrylate, caprolactone-modified tripentaerythritolpenta(meth)acrylate, caprolactone-modified tripentaerythritolhexa(meth)acrylate, caprolactone-modified tripentaerythritolhepta(meth)acrylate, caprolactone-modified tripentaerythritolocta(meth)acrylate;a product of reacting caprolactone-modified pentaerythritoltri(meth)acrylate and an acid anhydride, a product of reactingcaprolactone-modified dipentaerythritol penta(meth)acrylate and an acidanhydride, and a product of reacting caprolactone-modifiedtripentaerythritol hepta(meth)acrylate and an acid anhydride.

Note that in the specific examples of multifunctional acrylate indicatedhere, “(meth)acrylate” means “acrylate or methacrylate.” Furthermore,“caprolactone-modified” means that ring-opened caprolactone or aring-opened polymer of caprolactone has been introduced between analcohol-derived portion and a (meth)acryloyloxy group of a(meth)acrylate compound.

A commercial product can be used as the multifunctional acrylate.Examples of such a commercial product include A-DOD-N, A-HD-N, A-NOD-N,APG-100, APG-200, APG-400, A-GLY-9E, A-GLY-20E, A-TMM-3, A-TMPT, AD-TMP,ATM-35E, A-TMMT, A-9550, A-DPH, HD-N, NOD-N, NPG and TMPT (manufacturedby Shin-Nakamura Chemical Co., Ltd.); “ARONIX M-220”, “ARONIX M-325”,“ARONIX M-240”, “ARONIX M-270”, “ARONIX M-309”, “ARONIX M-310”, “ARONIXM-321”, “ARONIX M-350”, “ARONIX M-360”, “ARONIX M-305”, “ARONIX M-306”,“ARONIX M-450”, “ARONIX M-451”, “ARONIX M-408”, “ARONIX M-400”, “ARONIXM-402”, “ARONIX M-403”, “ARONIX M-404”, “ARONIX M-405”, and “ARONIXM-406” (manufactured by Toagosei Co., Ltd.); and “EBECRYL 11”, “EBECRYL145”, “EBECRYL 150”, “EBECRYL 40”, “EBECRYL 140”, “EBECRYL 180”, DPGDA,HDDA, TPGDA, HPNDA, PETIA, PETRA, TMPTA, TMPEOTA, DPHA, and EBECRYLseries (manufactured by Daicel-Cytec Co., Ltd.).

With regards to the depressions and protrusions in the groove alignmentfilm, a protrusion has a width of preferably 0.05 μm to 5 μm, and adepression has a width of preferably 0.1 μm to 5 μm. A difference indepth between a depression and protrusion is preferably 2 μm or less andmore preferably 0.01 μm to 1 μm. Such a range makes it possible toobtain a liquid crystal alignment with little alignment disorder.

The alignment film has a thickness which is ordinarily 10 nm to 10000nm, preferably 10 nm to 1000 nm, and more preferably 10 nm to 500 nm.

A method for applying the composition in accordance with an embodimentof the present invention can be a method similar to the example methodsindicated for applying the alignment polymer composition to a basematerial.

<Step (B)>

In a case where the composition in accordance with an embodiment of thepresent invention contains a solvent, the solvent is ordinarily removedfrom a coated film which has been formed. Examples of methods forremoving the solvent include natural drying, draught drying, heatdrying, and drying under reduced pressure.

The polymerizable liquid crystal compound contained in the coated filmwhich has been formed is ordinarily heated to a temperature equal to orgreater than a temperature at which the compound becomes a solution, andis then cooled to a temperature at which liquid crystal alignmentoccurs, so as to align the compound and form a liquid crystal phase.

The temperature for aligning the polymerizable liquid crystal compoundcontained in the coated film which has been formed can be found inadvance by, for example, texture observations using a compositioncontaining the polymerizable liquid crystal compound. The solventremoval and the liquid crystal alignment can be carried outsimultaneously. The temperature to be used in such a case will depend onthe type of solvent to be removed and the type of the polymerizableliquid crystal compound, but is preferably in a range of 50° C. to 200°C. In a case where the base material is a resin base material, thetemperature is more preferably in a range of 80° C. to 130° C.

In a case where the circularly polarizing plate is produced so as toinclude (i) a base material which is a quarter-wave plate and (ii) thepolarizing film in accordance with an embodiment of the presentinvention, an alignment direction of the polymerizable liquid crystalcompound can be set such that a substantially 45° angle is formed by thetransmission axis of the polarizing film to be produced and a slow axis(light axis) of the base material.

<Step (C)>

The polymerizable liquid crystal compound, having been aligned, ispolymerized by irradiating the polymerizable liquid crystal compoundwith an active energy ray.

Polymerizing the polymerizable liquid crystal compound having beenaligned makes it possible to obtain a polarizing film including (i) apolymerizable liquid crystal compound which has been polymerized in analigned state and (ii) a compound (1) having been aligned with thepolymerizable liquid crystal compound.

A polarizing film containing a polymerizable liquid crystal compoundwhich has been polymerized while retaining a smectic liquid crystalphase has (i) high polarizability in comparison to a conventionalhost-guest type polarizing film (i.e., a polarizing film in which, forexample, a polymerizable liquid crystal compound has been polymerizedwhile retaining a nematic liquid crystal phase) and (ii) superiorpolarizability and strength in comparison to a polarizing film obtainedby applying only a dichroic pigment or lyotropic liquid crystal-typeliquid crystal compound.

A light source for the active energy ray need only be a light sourcewhich generates ultraviolet rays, electron beams, X-rays, or the like.The light source is preferably one which has a light emissiondistribution such that wavelength is 400 nm or less, such as lowpressure mercury lamp, medium pressure mercury lamp, high pressuremercury lamp, super-high pressure mercury lamp, chemical lamp, blacklight lamp, microwave excitation mercury lamp, or metal halide lamp.

The irradiation energy of the active energy ray is set such that awavelength region effective for activation of the polymerizationinitiator has an irradiation intensity of preferably 10 mJ/cm² to 5000mJ/cm², and more preferably 100 mJ/cm² to 2000 mJ/cm². A irradiationenergy of less than 10 mJ/cm² tends to result in insufficient curing ofthe polymerizable liquid crystal compound.

The polarizing film, in accordance with an embodiment of the presentinvention, having been formed thusly, has a thickness that is preferablyin a range of 0.5 μm to 10 μm, and more preferably in a range of 1 μm to5 μm. The thickness of the polarizing film in accordance with anembodiment of the present invention can be found by measurements usingan interference thickness meter, a laser microscope, or stylus typethickness meter.

The polarizing film in accordance with an embodiment of the presentinvention is particularly preferably one in which a Bragg peak can beobtained in X-ray diffraction measurement. Examples of such a polarizingfilm in accordance with an embodiment of the present invention in whicha Bragg peak can be obtained include a polarizing film which exhibits adiffraction peak derived from a hexatic phase or crystal phase.

A maximum absorption (λ_(max1)) of the polarizing film in accordancewith an embodiment of the present invention preferably falls within arange of 350 nm to 550 nm, more preferably falls within a range of 410nm to 540 nm, and even more preferably falls within a range of 430 nm to530 nm. The λ_(max1) is preferably shifted to a longer wavelength incomparison to a maximum absorption (λ_(max2)) measured in a case wherethe compound (1) contained in the polarizing film in accordance with anembodiment of the present invention has been dissolved in a suitablesolvent. The shift to a longer wavelength is exhibited when the compound(1) is dispersed between molecular chains formed by the polymerizableliquid crystal compound which has been polymerized. The shift indicatesstrong interaction between the compound (1) and the molecular chain.“Shift to a longer wavelength” means that a difference betweenabsorption maxima (λ_(max1)−λ_(max2)) becomes a positive value. Thedifference is preferably 10 nm or more and is more preferably 30 nm ormore.

The polarizing film in accordance with an embodiment of the presentinvention exhibits a dichroic ratio which is preferably 50 or more, morepreferably 55 or more, still more preferably 60 or more, and furtherpreferably 70 or more.

In a case where the base material that is used is not a quarter-waveplate, it is possible to obtain the circularly polarizing plate bylaminating (i) the obtained polarizing film in accordance with anembodiment of the present invention and (ii) a quarter-wave plate toeach other. In such a case, it is preferable to dispose the polarizingfilm in accordance with an embodiment of the present invention and thequarter-wave plate in a manner such that a transmission axis of thepolarizing film and a slow axis (light axis) of the quarter-wave plateform an angle that is substantially 45°. It is also possible to obtain acircularly polarizing plate which functions as an optical compensationfilm by causing (i) the transmission axis of the polarizing film inaccordance with an embodiment of the present invention and (ii) thelight axis of a phase-difference film such as a quarter-wave plate to bealigned or to intersect orthogonally.

The polarizing film in accordance with an embodiment of the presentinvention and the quarter-wave plate can be laminated to each otheralong with a base material on which the polarizing film has been formedor a base material on which an alignment film has been formed. Thepolarizing film and the quarter-wave plate can alternatively belaminated to each other after the base material, or base material andalignment film, has/have been removed. Laminating (i) the polarizingfilm in accordance with an embodiment of the present invention, whichhas been formed on a base material or on a base material on which analignment film has been formed and (ii) the quarter-wave plate to eachother can be carried out by, for example, using an adhesive to bond thequarter-wave plate to a surface on which the polarizing film has beenformed, and then subsequently removing the base material or the basematerial on which the alignment film has been formed. In such a case,the adhesive may be applied to the polarizing film and/or to thequarter-wave plate.

<Method for Continuously Producing Polarizing Film in Accordance withEmbodiment of Present Invention>

A polarizing film in accordance with an embodiment of the presentinvention is preferably produced by continuous roll-to-roll production.The following description will discuss, with reference to FIG. 1, mainparts of a method continuous roll-to-roll production for the polarizingfilm in accordance with an embodiment of the present invention.

A first roll 210, in which a base material has been wound onto a firstcore 210A, can be easily obtained, for example, as a commercial product.Examples of such commercially available base materials in roll forminclude, among the example base materials already discussed above, filmsmade from cellulose ester, cyclic olefinic resin, polycarbonate,polyethylene terephthalate or polymethacrylic acid ester.

A base material P is wound off from the first roll 210. The basematerial P can be wound off by a method in which a suitable rotationmeans is provided to the core 210A of the first roll 210 and causes thefirst roll 210 to rotate. The base material P can alternatively be woundoff by a method in which at least one suitable auxiliary roll 300 isprovided in a direction in which the base material P is conveyed fromthe first roll 210, and a rotation means of the auxiliary roll 300 isused to wind off the base material P. The base material P canalternatively be wound off by a method in which respective rotationmeans are provided to the first core 210A and to the auxiliary roll 300so as to wind off the base material P while suitably tensioning the basematerial P.

After the base material P is wound off from the first roll 210, acoating device 211A applies a composition for photoalignment filmformation to the base material P as the base material P passes throughthe coating device 211A. Preferable methods for continuously applyingthe composition for photoalignment film formation via the coating device211A are gravure coating, die coating, and flexography.

After passing through the coating device 211A, the base material P isconveyed to a drying furnace 212A. The drying furnace 212A dries thecomposition for photoalignment film formation, thereby continuouslyforming a first coated film on a surface of the base material. Examplesof the drying furnace 212A include a hot air type drying furnace whichcombines draught drying and heat drying. A temperature to which thedrying furnace 212A is set is determined in accordance with, forexample, the type of the solvent contained in the composition forphotoalignment film formation. The drying furnace 212A can be configuredto include a plurality of zones each set to differing temperatures, orconfigured to include a plurality of drying furnaces which are providedin a linear manner and are each set to differing temperatures.

Next, a polarized UV light irradiation device 213A irradiates theobtained first coated film with polarized UV light so that aphotoalignment film is obtained.

Thereafter, the base material P having the photoalignment film formedthereon passes through a coating device 211B. The coating device 211Bapplies, to the photoalignment film, the composition in accordance withan embodiment of the present invention, which composition contains asolvent. Thereafter, the base material P passes through a drying furnace212B, so that a second coated film is obtained. In the second coatedfilm, the polymerizable liquid crystal compound contained in thecomposition in accordance with an embodiment of the present invention isaligned. The drying furnace 212B serves a role of removing the solventcontained in the composition in accordance with an embodiment of thepresent invention, after composition has been applied onto thephotoalignment film. The drying furnace 212B also serves a role ofproviding thermal energy so that the polymerizable liquid crystalcompound contained in the composition becomes aligned. Similarly to thedrying furnace 212A, the drying furnace 212B can be configured toinclude a plurality of zones each set to differing temperatures, orconfigured to include a plurality of drying furnaces which are providedin a linear manner and are each set to differing temperatures.

The base material P is conveyed to an active energy ray irradiationdevice 213B in a state where the polymerizable liquid crystal compoundcontained in the second coated film is aligned. The active energy rayirradiation device 213B irradiates the second coated film with activeenergy rays. This irradiation causes polymerization in a state where thepolymerizable liquid crystal compound is aligned, so that a polarizingfilm is obtained.

The polarizing film in accordance with an embodiment of the presentinvention, having been thusly continuously produced, is wound around asecond core 220A so as to be in the form of a second roll 220. Thepolarizing film may be wound together with a suitable spacer.

Thus, the polarizing film in accordance with an embodiment of thepresent invention can be produced in a continuous roll-to-roll manner byconveying the base material P from the first roll 210 through thecoating device 211A, the drying furnace 212A, the polarized UV lightirradiation device 213A, the coating device 211B, the drying furnace212B and the active energy ray irradiation device 213B, in this order.

The producing apparatus of FIG. 1 illustrates an example method in whichthe polarizing film in accordance with an embodiment of the presentinvention is produced continuously. It is also possible, however, toproduce the polarizing film in accordance with an embodiment of thepresent invention by a method in which, for example, (i) the basematerial P is conveyed from the first roll 210 through the coatingdevice 211A, the drying furnace 212A, and the polarized UV lightirradiation device 213A in this order, (ii) thereafter, the basematerial and the photoalignment film are wrapped around a core toproduce a laminated body in the form of a roll, and then (iii) thelaminated body is unwound and passed through the coating device 211B anddrying furnace 212B, and the active energy ray irradiation device 213Bin this order.

In a case where the polarizing film in accordance with an embodiment ofthe present invention is produced in the form of the second roll 220, acircularly polarizing plate can be produced by (i) winding off thepolarizing film, which is long, from the second roll 220, (ii) cuttingthe polarizing film to a predetermined dimension, and (iii) bonding aquarter-wave plate to the polarizing film thus cut. Alternatively, along circularly polarizing plate can be produced continuously bypreparing a third roll (not shown) obtained by winding a longquarter-wave plate onto a core.

The following description will discuss, with reference to the producingapparatus illustrated in FIG. 2, an example method for continuouslyproducing a long circularly polarizing plate. The method includes thesteps of (i) continuously winding off a polarizing film Q in accordancewith an embodiment of the present invention from the second roll 220wound around the second core 220A and concurrently continuously windingoff a long quarter-wave plate S from a third roll 230 obtained bywinding a long quarter-wave plate onto a third core 230A, (ii) obtaininga long circularly polarizing plate QS by continuously bonding thepolarizing film Q and the long quarter-wave plate S to each other, and(iii) obtaining a fourth roll 240 by winding the long circularlypolarizing plate QS thus obtained onto a fourth core 240A.

The polarizing film Q and the quarter-wave plate S can be wound off byusing a method in which suitable respective rotation means are providedto the core 220A of the second roll 220 and the core 230A of the thirdroll 230, and the respective rotation means cause the second roll 220and the third roll 230 to rotate. The polarizing film Q and thequarter-wave plate S can alternatively be wound off by a method in whichat least one suitable auxiliary roll 300 is provided in a direction inwhich the polarizing film Q and the quarter-wave plate S are conveyed,and a rotation means of the auxiliary roll 300 is used to wind off thepolarizing film Q and the quarter-wave plate S. The polarizing film Qand the quarter-wave plate S can alternatively be wound off by a methodin which respective rotation means are provided to the core 220A, thecore 230A, and the auxiliary roll 300 so as to wind off the polarizingfilm Q and the quarter-wave plate S while suitably tensioning thepolarizing film Q and the quarter-wave plate S. Such methods are knownas roll-to-roll bonding. Note that an adhesive may be used for thebonding.

<Application of Polarizing Film in Accordance with Embodiment of PresentInvention>

A polarizing film in accordance with an embodiment of the presentinvention and a circularly polarizing plate including the polarizingfilm and a quarter-wave plate can be used for various display devices.

A display device is a device including: a display element; and alight-emitting element or a light-emitting device serving as alight-emitting source. Examples of the display device including thepolarizing film in accordance with an embodiment of the presentinvention encompass a liquid crystal display device, an organicelectroluminescent (EL) display device, an inorganic electroluminescent(EL) display device, an electron emission display device (e.g. a fieldemission display device (FED), a surface-conduction electron-emitterdisplay device (SED)), electronic paper (a display device which employselectronic ink or an electrophoretic element), a plasma display device,projection display devices (e.g. a grating light valve (GLV) displaydevice and a display device including a digital micromirror device(DMD)), and a piezoelectric ceramic display. Examples of the liquidcrystal display device encompass: a transmissive liquid crystal displaydevice, a semi-transmissive liquid crystal display device, a reflectiveliquid crystal display device, a direct-view liquid crystal displaydevice, and a projection liquid crystal display device. Each of thosedisplay devices can be a display device which displays a two-dimensionalimage or can be a stereoscopic display device which displays athree-dimensional image.

The polarizing film in accordance with an embodiment of the presentinvention can be used particularly effectively for a liquid crystaldisplay device, an organic electroluminescent (EL) display device, andan inorganic electroluminescent (EL) display device. The organic ELdisplay device includes at least: the polarizing film in accordance withan embodiment of the present invention; and an organic EL element. Theorganic EL element can be an element having a publicly knownconfiguration.

The circularly polarizing plate including the polarizing film inaccordance with an embodiment of the present invention and aquarter-wave plate can be used particularly effectively for an organicelectroluminescent (EL) display device and an inorganicelectroluminescent (EL) display device. The organic EL display deviceincludes at least: a circularly polarizing plate in accordance with anembodiment of the present invention; and an organic EL element.

In a case where the polarizing film in accordance with an embodiment ofthe present invention is used for a liquid crystal display device, thepolarizing film can be provided outside or inside a liquid crystal cell.The liquid crystal cell includes at least: the polarizing film inaccordance with an embodiment of the present invention; a liquid crystallayer; and a base.

The following description will discuss, with reference to FIG. 3, afirst configuration of particularly a transmissive active-matrix colorliquid crystal display device in a case where a polarizing film inaccordance with an embodiment of the present invention is providedinside a liquid crystal cell of the display device. The display device30 is configured so that a first base 31, a first polarizing film 32 inaccordance with an embodiment of the present invention, a color filterlayer (color filter) 33, a planarizing layer 34, an ITO electrode layer35, a first alignment film 36, a liquid crystal layer 37, a secondalignment film 38, a second polarizing film 39 in accordance with anembodiment of the present invention, a TFT layer 40 including a thinfilm transistor circuit and a pixel electrode, and a second base 41 arelaminated in this order. These layers can be laminated by a publiclyknown method.

The first polarizing film 32 in accordance with an embodiment of thepresent invention is provided between the first base 31 and the liquidcrystal layer 37.

The color filter layer 33 is provided between the first base 31 and theliquid crystal layer 37 so as to take out, from light entering thedisplay device from a first base 31-side, light having a desiredwavelength. The color filter layer 33 can be, for example, (i) a layerwhich absorbs, from white light, a light having any wavelength otherthan a desired wavelength, so as to allow only light having the desiredwavelength to pass through the layer or (ii) a layer which converts awavelength of light, which has entered the display device, so as to emitlight having a desired wavelength.

The first polarizing film 32 in accordance with an embodiment of thepresent invention can include an alignment film on a first base 31-sidethereof. The second polarizing film 39 in accordance with an embodimentof the present invention can include an alignment film on a second base41-side thereof. Each of the first alignment film 36 and the secondalignment film 38 can be a rubbed alignment film or a photo-alignmentfilm. The first polarizing film 32 in accordance with an embodiment ofthe present invention can include a phase-difference layer.

A second configuration of the display device will be described next withreference to FIG. 4. A display device 60 is configured so that a firstbase 61, a first polarizing film 62 in accordance with an embodiment ofthe present invention, a color filter layer (color filter) 63, aplanarizing layer 64, an ITO electrode layer 65, a first alignment film66, a liquid crystal layer 67, a second alignment film 68, a TFT layer70 including a thin film transistor circuit and a pixel electrode, asecond base 71, and a second polarizing film 72 are laminated in thisorder. These layers can be laminated by a publicly known method.

The second polarizing film 72, which is located so as to face the TFTlayer 70 via the second base 71, can be (i) a polarizing film inaccordance with an embodiment of the present invention or (ii) apolarizing film which is produced by dyeing polyvinyl alcohol withiodine and then stretching the polyvinyl alcohol thus dyed.

A third configuration of the display device will be described next withreference to FIG. 5. A display device 80 is configured so that a firstbase 81, a color filter layer (color filter) 82, a first polarizing film83 in accordance with an embodiment of the present invention, aplanarizing layer 84, an ITO electrode layer 85, a first alignment film86, a liquid crystal layer 87, a second alignment film 88, a TFT layer90 including a thin film transistor circuit and a pixel electrode, asecond base 91, and a second polarizing film 92 are laminated in thisorder. These layers can be laminated by a publicly known method.

In the third configuration, the second polarizing film 92 can be (i) apolarizing film in accordance with an embodiment of the presentinvention or (ii) a polarizing film which is produced by dyeingpolyvinyl alcohol with iodine and then stretching the polyvinyl alcoholthus dyed. In a case where the second polarizing film 92 is a polarizingfilm in accordance with an embodiment of the present invention, thesecond polarizing film 92 can be located between the second base 91 andthe TFT layer 90 as in the first configuration.

In the third configuration, the color filter layer 82 can be provided sothat the first base 81 is located between the color filter layer 82 andthe liquid crystal layer 87.

Note that there is a possibility that particles, which are contained inthe color filter layer, cause polarized light to be scattered, so thatthe polarized light become depolarized. Therefore, among the firstconfiguration to the third configuration, the third configuration, inwhich the first polarizing film in accordance with an embodiment of thepresent invention is located closer to the liquid crystal layer than isthe color filter layer, is preferable. That is, a display device havingthe third configuration is preferable.

The present invention is not limited to the embodiments described above,but can be altered by a skilled person in the art within the scope ofthe claims. An embodiment derived from a proper combination of technicalmeans each disclosed in a different embodiment is also encompassed inthe technical scope of the present invention. It is also possible toform a new technical feature by combining the technical means disclosedin the respective embodiments.

EXAMPLES

The following description will discuss the present invention in moredetail with reference to Examples. However, the present invention shouldnot be limited to the Examples below. Note that expressions “%” and“parts” in Examples refer to “% by mass” and “parts by mass”,respectively, unless particularly stated otherwise.

Production Example 1

2.0 g of a compound represented by Formula (2a-1), 20 g of acetic acid,2.0 g of water, and 2.6 g of 35% hydrochloric acid were mixed. Aresultant mixture was cooled to 0° C., and then 1.6 g of 33% aqueoussodium nitrite solution was dropped on the mixture. A resultant mixturewas stirred for 30 minutes, and 0.07 g of amidosulfonic acid was added.A resultant mixture was dropped at 0° C. on a mixture of (i) 1.64 g of acompound represented by Formula (2b-1), (ii) 2.33 g of sodium acetate,and (iii) 24.6 g of water. Then, a deposit containing a compoundrepresented by Formula (3a-1) was filtered, and was washed with water 3times.

To a resultant deposit, 3.0 g of sodium hydroxide and 60 g of water wereadded. A resultant mixture was stirred at 85° C. for 2 hours, and wasthen cooled to 10° C. A resultant deposit was filtered, and was washedwith water. A resultant solid substance was dried, so that 1.97 g of anorange solid substance containing a compound represented by Formula(3b-1) was obtained.

1.20 g of the orange solid substance thus obtained, 2.01 g ofN,N-diisopropylethylamine, and 12.0 g of N,N-dimethylacetamide weremixed, and then 2.68 g of 2-iodoethanol was dropped on the resultantmixture. A resultant mixture was stirred at 120° C. for 2 hours. Aresultant reaction mixture was dropped on methanol, and then a depositwas filtered and then dried, so that 1.17 g of a compound represented byFormula (1a-5) (hereinafter referred to as “compound (1a-5)”) wasobtained.

Production Example 2

1.25 g of a compound represented by Formula (1a-1) (hereinafter referredto as “compound (1a-1)”) was obtained as in Production Example 1 exceptthat a compound represented by Formula (2a-2) was used instead of thecompound represented by Formula (2a-1).

Production Example 3

1.33 g of a compound represented by Formula (1a-2) (hereinafter referredto as “compound (1a-2)”) was obtained as in Production Example 1 exceptthat a compound represented by Formula (2a-3) was used instead of thecompound represented by Formula (2a-1).

Production Example 4

1.11 g of a compound represented by Formula (1a-7) (hereinafter referredto as “compound (1a-7)”) was obtained as in Production Example 1 exceptthat a compound represented by Formula (2a-4) was used instead of thecompound represented by Formula (2a-1).

Example 1

To a mixture of 2.14 g of a 36% aqueous formaldehyde solution and 11.0 gof methanol, 1.10 g of the compound (1a-5) obtained in ProductionExample 1 was added, and a resultant mixture was stirred at 60° C. for18 hours. After the mixture was cooled to 20° C., the mixture wasfiltered, so that a solid substance was obtained. The solid substancewas dried, and then purified by silica gel column chromatography(eluate: chloroform). A resultant solid substance was washed withacetonitrile and then dried, so that 0.20 g of a compound, which is ared solid substance and is represented by Formula (1-5) (hereinafterreferred to as “compound (1-5)”), was obtained.

Yield (based on compound (1-5)): 18%

M/Z: 442 (EI-MS)

Maximum absorption wavelength (λ_(max2))=450 nm (chloroform solution)

Example 2

0.088 g of a compound represented by Formula (1-1) (hereinafter referredto as “compound (1-1)”) was obtained by carrying out operation andreaction as in Example 1 except that the compound (1a-1) obtained inProduction Example 2 was used instead of the compound (1a-5).

Yield (based on compound (1-1)): 7%

M/Z: 426 (EI-MS)

Maximum absorption wavelength (λ_(max2))=⁴⁵⁸ nm (chloroform solution)

¹H-NMR (CDCl₃) of compound (1-1): δ (ppm) 2.80 (t, 2H), 4.03 (t, 2H),4.53 (t, 2H), 7.43 (m, 2H), 7.56 (m, 2H), 7.75 (c, 4H), 8.02 (c, 4H)

Example 3

0.165 g of a compound represented by Formula (1-2) (hereinafter referredto as “compound (1-2)”) was obtained by carrying out operation andreaction as in Example 1 except that the compound (1a-2) obtained inProduction Example 3 was used instead of the compound (1a-5).

Yield (based on compound (1-2)): 15%

M/Z: 414 (EI-MS)

Maximum absorption wavelength (λ_(max2))=⁴⁴⁴ nm (chloroform solution)

¹H-NMR (CDCl₃) of compound (1-2): δ (ppm) 0.95 (t, 3H), 1.35 (m, 2H),1.66 (m, 2H), 2.70 (t, 2H), 3.55 (t, 2H), 4.23 (t, 2H), 4.98 (s, 2H),6.60 (m, 2H), 7.34 (m, 2H), 7.87 (m, 2H), 7.95 (m, 2H), 8.02 (c, 4H)

Example 4

0.070 g of a compound represented by Formula (1-7) (hereinafter referredto as “compound (1-7)”) was obtained by carrying out operation andreaction as in Example 1 except that the compound (1a-7) obtained inProduction Example 4 was used instead of the compound (1a-5).

Yield (based on compound (1-7)): 5%

M/Z: 400 (EI-MS)

Maximum absorption wavelength (λ_(max2))=⁴⁶⁶ nm (chloroform solution)

[Polymerizable Liquid Crystal Compound]

The following compounds were used: a compound represented by thefollowing Formula (4-6) (hereinafter referred to as “compound (4-6)”); acompound represented by the following Formula (4-8) (hereinafterreferred to as “compound (4-8)”); a compound represented by thefollowing Formula (4-22) (hereinafter referred to as “compound (4-22)”);and a compound represented by the following Formula (4-25) (hereinafterreferred to as “compound (4-25)”).

Note that the compound (4-6) was synthesized by the method disclosed inLub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996). The compound(4-8) was also produced in conformity with this method. The compound(4-22) and the compound (4-25) were each produced in conformity with themethod disclosed in Japanese Patent No. 4719156.

[Measurement of Phase Transition Temperature]

The phase transition temperatures of the polymerizable liquid crystalcompounds described above were measured by obtaining phase transitiontemperatures of films derived from the respective polymerizable liquidcrystal compounds as described below.

A film derived from the compound (4-6) was formed on a glass substrateon which an alignment film was formed. Then, while the film derived fromthe compound (4-6) was being heated, a phase transition temperature wasmeasured by texture observation with use of a polarizing microscope(BX-51, manufactured by Olympus Corporation).

The results showed that while a temperature of the compound (4-6) wasfalling after rising to 120° C., a phase of the compound (4-6)transitioned to a nematic phase at 112° C., to a smectic A phase at 110°C., and to a smectic B phase at 94° C.

As in the measurement of the phase transition temperature of thecompound (4-6), the phase transition temperature of the compound (4-8)was measured.

The results showed that while a temperature of the compound (4-8) wasfalling after rising to 140° C., a phase of the compound (4-8)transitioned to a nematic phase at 131° C., to a smectic A phase at 80°C., and to a smectic B phase at 68° C.

As in the measurement of the phase transition temperature of thecompound (4-6), the phase transition temperature of the compound (4-22)was measured.

The results showed that while a temperature of the compound (4-22) wasfalling after rising to 140° C., a phase of the compound (4-22)transitioned to a nematic phase at 106° C., to a smectic A phase at 103°C., and to a smectic B phase at 86° C.

As in the measurement of the phase transition temperature of thecompound (4-6), the phase transition temperature of the compound (4-25)was measured.

The results showed that while a temperature of the compound (4-25) wasfalling after rising to 140° C., a phase of the compound (4-25)transitioned to a nematic phase at 119° C., to a smectic A phase at 100°C., and to a smectic B phase at 77° C.

Example 5

[Preparation of Composition]

The following components were mixed and stirred at 80° C. for 1 hour, sothat a composition (1) was obtained:

Compound (1); 2.5 parts of the compound (1-5)

Polymerizable liquid crystal compound;

-   -   75 parts of the compound (4-6)    -   25 parts of the compound (4-8)

Polymerization initiator; 6 parts of2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butane-1-one(Irgacure369, manufactured by Ciba Specialty Chemicals Inc.)

Leveling agent; 1.5 parts of a polyacrylate compound (BYK-361N;manufactured by BYK-Chemie GmbH)

Solvent; 250 parts of chloroform

[Measurement of Phase Transition Temperature]

As in the measurement of the phase transition temperature of thecompound (4-6), a phase transition temperature of components containedin the composition (1) was measured.

The results showed that while a temperature of the components wasfalling after rising to 140° C., a phase of the components transitionedto a nematic phase at 115° C., to a smectic A phase at 105° C., and to asmectic B phase at 75° C.

[Production and Evaluation of Polarizing Film]

1. Formation of Alignment Film

A glass substrate was coated, by a spin coating method, with a 2 mass %aqueous solution of polyvinyl alcohol (Poly(vinyl Alcohol) 1000,completely saponified, manufactured by Wako Pure Chemical Industries,Ltd.), and then dried. Then, a film having a thickness of 100 nm wasformed. Then, a surface of the film thus obtained was subjected to arubbing treatment, so that an alignment film was formed. The rubbingtreatment was carried out (i) by use of a semi-automatic rubbing device(product name: LQ-008 type, manufactured by Joyo Engineering Co., Ltd.),(ii) with the use of cloth (product name: YA-20-RW, manufactured byYoshikawa Chemical Co., Ltd.), and (iii) under conditions where: thepushing amount was 0.15 mm; and the rotation speed was 500 rpm and 16.7mm/s. By the rubbing treatment, a laminated body 1, in which thealignment film was provided on the glass substrate, was obtained.

2. Formation of Polarizing Film

The alignment film of the laminated body 1 was coated with thecomposition (1) by a spin coating method, dried by heating on a hotplate at 120° C. for 1 minute, and then rapidly cooled to roomtemperature, so that a dry film containing an aligned polymerizableliquid crystal compound was formed on the alignment film. Then, with useof a UV light irradiation device (SPOT CURE SP-7; manufactured by UshioInc.), the dry film was irradiated with ultraviolet light of a lightexposure of 2000 mJ/cm² (based on a wavelength of 365 nm). This allowedthe polymerizable liquid crystal compound to be polymerized while analignment status was maintained, so that a laminated body 2, in which apolarizing film (1) was formed from the dry film, was obtained. In sodoing, a thickness of the polarizing film, which was measured with alaser microscope (OLS3000 manufactured by Olympus Corporation), was 1.7μm.

3. X-Ray Diffraction Measurement

The polarizing film (1) was subjected to X-ray diffraction measurementwith use of an X-ray diffraction instrument X′Pert PRO MPD (manufacturedby Spectris Co., Ltd.). A rubbing direction of an alignment film under apolarizing film had been obtained in advance. Then, with use of Cu as atarget, an X-ray, which was generated at an electric current of 40 mAand a voltage of 45 kV in an X-ray tube, entered the polarizing film(1), via a fixed divergence slit ½°, in the rubbing direction. Then, themeasurement was carried out by scanning an angle at which the X-rayentered the polarizing film (1), in a range of 2θ=4.0° to 40.0° in stepsof 2θ=0.016710. This resulted in a sharp diffraction peak (Bragg peak)which appeared in the vicinity of 2θ=20.1° and which had a half-valuewidth of the peak (FWHM) of approximately 0.310. In a case where anX-ray entered the polarizing film (1) in a direction perpendicular tothe rubbing direction, similar results were obtained. An order period(d) obtained based on the peak point was approximately 0.44 nm. Thisindicates that a structure reflecting a higher-order smectic phase wasformed.

4. Measurement of Dichroic Ratio

An absorbance (A′) along a transmission axis and an absorbance (A²)along an absorption axis at a maximum absorption wavelength weremeasured (i) with use of a device obtained by setting, onto aspectrophotometer (UV-3150, manufactured by Shimadzu Corporation), afolder which includes the laminated body 2 and (ii) by a double beammethod. On a reference side of the folder, a mesh for cutting an amountof light by 50% was provided. Based on the absorbance (A¹) along thetransmission axis and the absorbance (A²) along the absorption axis thusmeasured, a ratio (A²/A¹) was calculated, and was treated as a dichroicratio. The maximum absorption wavelength (λ_(max1)) was 501 nm, and thedichroic ratio at this wavelength was such a high value as 63. It can besaid that a polarizing film having a higher dichroic ratio is moreuseful. As described in Example 1, since a maximum absorption wavelength(λ_(max2)) of the compound (1-5) is 450 nm, it was confirmed that themaximum absorption wavelength (λ_(max2)) was shifted to a longerwavelength. This result showing the shifting of the maximum absorptionwavelength to a longer wavelength indicates the following: In a casewhere the compound (1-5) is dispersed between dense molecular chainsobtained by polymerization of a polymerizable liquid crystal compound ina polarizing film in accordance with an embodiment of the presentinvention, the compound (1-5) and the molecular chains interact closelywith each other.

A light-resistance was also evaluated by (i) providing a protection film(40-μm TAC “KC4UY” manufactured by Konica Minolta, Inc.) on a surface ofthe polarizing film (1) and (ii) irradiating the surface with light fromabove under the conditions described below. An absorbance of thepolarizing film (1) after the light-resistance test at the maximumabsorption wavelength (of 501 nm) of the polarizing film (1) was 82% ofthe light-resistance before the test. Meanwhile, a light-resistance testwas carried out on a polarizing film formed by a method similar to thatdescribed above with use of a dichroic pigment represented by theFormula (1-10) disclosed in Japanese Patent Application Publication,Tokukai, No. 2013-101328. The results showed that an absorbance of thepolarizing film after the light-resistance test at the maximumabsorption wavelength (of 548 nm) of the polarizing film was 47% of thelight-resistance before the test. That is, it was confirmed that thecompound in accordance with an embodiment of the present invention issuperior in light-resistance.

Light irradiation in the light-resistance test was carried out under thefollowing conditions:

-   -   Device used: SUNTEST XLS+ manufactured by ATLAS    -   Light source used: xenon arc lamp    -   Exposure conditions: 250 mW/m²    -   Testing time: 120 hours    -   Exposure amount: 108000 KJ/m²    -   Temperature: 60° C.

Example 6

A polarizing film was formed as in Example 5 except that the compound(1-1) obtained in Example 2 was used instead of the compound (1-5).Then, a maximum absorption wavelength and a dichroic ratio were measuredas in Example 5.

The results showed that the maximum absorption wavelength (λ_(max)i) was508 nm, and the dichroic ratio at this wavelength was such a high valueas 70. As described in Example 2, since a maximum absorption wavelength(λ_(max2)) of the compound (1-1) is 458 nm, it was confirmed that themaximum absorption wavelength (λ_(max2)) was shifted to a longerwavelength. This result showing the shifting of the maximum absorptionwavelength to a longer wavelength indicates the following: In a casewhere the compound (1-1) is dispersed between dense molecular chainsobtained by polymerization of the polymerizable liquid crystal compoundin a polarizing film in accordance with an embodiment of the presentinvention, the compound (1-1) and the molecular chains interact closelywith each other.

Example 7

A polarizing film was formed as in Example 5 except that the compound(1-2) obtained in Example 3 was used instead of the compound (1-5).Then, a maximum absorption wavelength and a dichroic ratio were measuredas in Example 5.

The results showed that the maximum absorption wavelength (λ_(max1)) was494 nm, and the dichroic ratio at this wavelength was such a high valueas 61. As described in Example 3, since a maximum absorption wavelength(λ_(max2)) of the compound (1-2) is 444 nm, it was confirmed that themaximum absorption wavelength (λ_(max2)) was shifted to a longerwavelength. This result showing the shifting of the maximum absorptionwavelength to a longer wavelength indicates the following: In a casewhere the compound (1-2) is dispersed between dense molecular chainsobtained by polymerization of a polymerizable liquid crystal compound ina polarizing film in accordance with an embodiment of the presentinvention, the compound (1-2) and the molecular chains interact closelywith each other.

Example 8

A polarizing film was formed as in Example 5 except that the compound(1-7) obtained in Example 4 was used instead of the compound (1-5).Then, a maximum absorption wavelength and a dichroic ratio were measuredas in Example 5.

The results showed that the maximum absorption wavelength (λ_(max1)) was508 nm, and the dichroic ratio at this wavelength was such a high valueas 83. As described in Example 4, since a maximum absorption wavelength(λ_(max2)) of the compound (1-7) is 466 nm, it was confirmed that themaximum absorption wavelength (λ_(max2)) was shifted to a longerwavelength. This result showing the shifting of the maximum absorptionwavelength to a longer wavelength indicates the following: In a casewhere the compound (1-7) is dispersed between dense molecular chainsobtained by polymerization of a polymerizable liquid crystal compound ina polarizing film in accordance with an embodiment of the presentinvention, the compound (1-7) and the molecular chains interact closelywith each other.

INDUSTRIAL APPLICABILITY

A compound in accordance with an embodiment of the present invention isa novel compound serving as a dichroic pigment which has a maximumabsorption wavelength in a range of 350 nm to 510 nm. The compoundallows a polarizing film, which has a high dichroic ratio, to beobtained from a composition containing the compound. A compound inaccordance with an embodiment of the present invention and a compositioncontaining the compound can each be widely used in the fields ofproducing (i) a polarizing film, (ii) a liquid crystal display deviceincluding a polarizing film, (iii) a liquid crystal cell including apolarizing film, (iv) a circularly polarizing plate including apolarizing film, and (v) an organic EL display device including apolarizing film.

REFERENCE SIGNS LIST

-   -   210 First roll    -   210A Core    -   211A, 211B Coating device    -   212A, 212B Drying furnace    -   213A Polarized UV light irradiation device    -   213B Active energy ray irradiation device    -   220 Second roll    -   220A Core    -   230 Third roll    -   230A Core    -   240 Fourth roll    -   240A Core    -   300 Auxiliary roll

1. A compound represented by the following Formula (1):

where: R¹ represents a hydrogen atom, a C1-C20 alkyl group, a C1-C20alkoxy group, a C1-C20 acyl group, a C2-C20 alkoxycarbonyl group, aC1-C20 acyloxy group, or —N(R¹⁰)(R¹¹); R¹⁰ represents a C1-C20 acylgroup, a C1-C20 alkylsulfonyl group, or a C6-C20 arylsulfonyl group; R¹¹represents a hydrogen atom or a C1-C20 alkyl group; R¹⁰ and R¹¹ can bondto each other, and form, with a nitrogen atom to which R¹⁰ and R¹¹ bond,a ring including —N—CO— or —N—SO₂—; at least one hydrogen atom of any ofthe alkyl group, the alkoxy group, the acyl group, the alkoxycarbonylgroup, the acyloxy group, the alkylsulfonyl group, and the arylsulfonylgroup can be substituted by a halogen atom, a hydroxy group, anunsubstituted amino group, or a substituted amino group; —O— or —NR²⁰—can be inserted between carbon atoms of any of the alkyl group and thealkoxy group; and R²⁰ represents a hydrogen atom or a C1-C20 alkylgroup; R² through R⁴ are substituents which are not hydrogen atoms andeach independently represent a C1-C4 alkyl group, a C1-C4 alkoxy group,a halogen atom, or a cyano group; at least one hydrogen atom of any ofthe alkyl group and the alkoxy group can be substituted by a halogenatom or a hydroxy group; and n, m, and p are each independently aninteger of 0 to 2; and Ar¹ represents a nitrogen-containing saturatedheterocyclic group which is a 5 to 8-membered ring and in which (i) N isbonded to a phenylene group and (ii) at least one β-position is anoxygen atom or a sulfur atom, and 1 to 6 of hydrogen atoms bonded to aring of the nitrogen-containing saturated heterocyclic group can besubstituted by a C1-C3 alkyl group.
 2. The compound as set forth inclaim 1, wherein the compound is represented by the following Formula(1′):

where: R¹ is identical to R¹ of Formula 1; and A represents an oxygenatom or a sulfur atom.
 3. The compound as set forth in claim 1, whereinthe compound has a maximum absorption wavelength in a range of 350 nm to510 nm.
 4. A composition comprising: a polymerizable liquid crystalcompound; and a compound recited in claim
 1. 5. The composition as setforth in claim 4, wherein the polymerizable liquid crystal compoundexhibits a smectic liquid crystal phase.
 6. The composition as set forthin claim 4, further comprising: a polymerization initiator.
 7. Apolarizing film comprising: a compound recited in claim
 1. 8. Thepolarizing film as set forth in claim 7, wherein a maximum absorptionwavelength (λ_(max1)) of the polarizing film is longer than a maximumabsorption wavelength (λ_(max2)) of the compound represented by theFormula (1) or the Formula (1′).
 9. The polarizing film as set forth inclaim 8, wherein a difference between the λ_(max1) and the λ_(max2) is10 nm or more.
 10. The polarizing film as set forth in claim 7, whereinthe polarizing film exhibits a Bragg peak in X-ray diffractionmeasurement.
 11. A liquid crystal display device comprising: apolarizing film recited in claim
 7. 12. A liquid crystal cellcomprising: a polarizing film recited in claim 7; a liquid crystallayer; and a base.
 13. The liquid crystal cell as set forth in claim 12,wherein the polarizing film is provided between the base and the liquidcrystal layer.
 14. The liquid crystal cell as set forth in claim 13,further comprising: a color filter provided between the base and theliquid crystal layer.
 15. A circularly polarizing plate comprising: apolarizing film recited in any claim 7; and a quarter-wave plate.
 16. Anorganic EL display device comprising: a polarizing film recited in claim7; and an organic EL element.
 17. An organic EL display devicecomprising: a circularly polarizing plate recited in claim 15; and anorganic EL element.